Radiation-sensitive devices with a composite semiconductor structure for detecting radiation

Abstract

A radiation-sensitive device that can detect radiation includes a plurality of semiconductor structures. Different semiconductor structures comprise different semiconductor materials, and the semiconductor structures are architecturally and functionally integrated such that charge carriers generated by incident radiation in one or more of the semiconductor structures cause the generation of additional charge carriers within the composite semiconductor structure, thereby producing an intrinsic charge-amplification effect that enhances a signal-to-noise ratio of the radiation-sensitive device. A plurality of electrodes is configured to apply an electric field across the composite semiconductor structure.

Description

[0001] Attorney Docket No. cap-oi6pct

[0002] RADIATION-SENSITIVE DEVICES WITH A COMPOSITE SEMICONDUCTOR STRUCTURE FOR DETECTING RADIATION RELATED APPLICATION

[0003] This application claims the benefit of U.S. Provisional Application No.

[0004] 63 / 705,159, filed 9 October 2024, the entire content of which is incorporated herein by reference.

[0005] GOVERNMENT SUPPORT

[0006] This invention was made with US government support under Grant No.

[0007] R44EB028208 awarded by the National Institutes of Health. The US government has certain rights in the invention.

[0008] BACKGROUND

[0009] The discussion of the background state of the art below may reflect hindsight gained from the disclosed invention(s), and these characterizations are not necessarily admitted to be prior art.

[0010] The field of radiation detection has seen significant advancements over the years, driven by the need for more sensitive and more accurate devices. Radiation detectors are highly advantageous in various applications, including medical imaging, security screening, and scientific research. Traditional radiation detectors often face challenges, such as limited sensitivity and high noise levels, which can affect their performance and reliability. These limitations leave room for improvement in terms of the development of new materials and structures that can improve the efficiency and accuracy of radiation detection.

[0011] Semiconductors have long been used in radiation detection due to their ability to convert incoming radiation into electrical signals. The performance of semiconductorbased detectors, however, can be hindered by factors such as charge-carrier recombination and dark-current noise. Charge-carrier recombination is the process in which free electrons and holes in a semiconductor material recombine, releasing energy as they return to their lower energy states. Meanwhile, dark-current noise is the statistical variation in the number of electrons thermally generated within a sensor pixel, independent of incoming photons. Dark-current noise is due to random events on the atomic scale in the detector and is a form of thermal noise that can degrade image quality, especially during long exposures.

[0012] To address these issues, we explore the use of semiconductor materials and structures that can enhance charge transport and reduce noise. The integration of different semiconductor materials, such as organic, inorganic, and hybrid structures, offers the potential to overcome these challenges and to achieve higher sensitivity andAttorney Docket No. cap-oi6pct

[0013] lower noise levels in radiation detectors. As the demand for more advanced radiation detection technologies continues to grow, innovations in semiconductor materials and device architectures remain a key area of research and development.

[0014] SUMMARY

[0015] A radiation-sensitive device and a method for detecting radiation therewith are described herein, where various implementations of the device and methods may include some or all of the elements, features, and steps described below.

[0016] The radiation-sensitive device can detect radiation and includes a plurality of semiconductor structures. Different semiconductor structures comprise different semiconductor materials, and the semiconductor structures are architecturally and functionally integrated such that charge carriers generated by incident radiation in one or more of the semiconductor structures cause the generation of additional charge carriers within the composite semiconductor structure, thereby producing an intrinsic charge-amplification effect that enhances a signal-to-noise ratio of the radiationsensitive device. A plurality of electrodes is configured to apply an electric field across the composite semiconductor structure.

[0017] The composite semiconductor structure can be integrated into a field-effect transistor (FET) architecture, wherein at least one of the semiconductor structures forms a radiation-sensitive channel, and wherein the electrodes comprise interdigitated source and drain electrodes, such that radiation-generated charge carriers in the channel modulate a current between the source and drain electrodes to produce the intrinsic charge-amplification effect.

[0018] The semiconductor structure can form a superlattice of alternating thin layers, wherein quantum confinement effects within the superlattice are engineered to enhance impact ionization, contributing to the intrinsic charge-amplification effect.

[0019] Further still, optical structures can be integrated with the composite semiconductor structure, wherein the optical structures are configured to trap and recycle secondary photons generated within the device, thereby stimulating further charge generation to produce the intrinsic charge-amplification effect.

[0020] At least one of the semiconductor structures can be in the form of quantum dots capable of multiple exciton generation (MEG), such that a single high-energy incident photon generates multiple electron-hole pairs, producing the intrinsic chargeamplification effect.

[0021] One or more of the semiconductors can act as blocking or charge-transport layers that can enhance charge propagation under an electric field and that can also generate charge carriers from the incoming radiation, thereby generating an intrinsic charge-amplification effect, which may increase the sensitivity of the device while regulating the dark-current noise.Attorney Docket No. cap-oi6pct

[0022] The device may be configured as an X-ray flat panel radiation detector.

[0023] The device can also incorporate a scintillator material into the multi-layered semiconductor structure. The scintillator material may be selected from compositions such as cesium iodide, sodium iodide, bismuth germanate, lutetium oxyorthosilicate, or gadolinium oxyorthosilicate. The scintillator material can be in the form of a layer placed on top of or between the semiconductor structures or may also be embedded within one or more of the semiconductor structures. Alternatively, the semiconductor structures can be in the form of layers, and the layers can be progressively doped or mixed into one another to create a smooth transition between the layers.

[0024] The device may include nanostructures of a first material in a matrix of at least one of the semiconductor materials to create localized charge-amplification sites.

[0025] The semiconductor structures can be heterostructures or superlattices of alternating layers of different semiconductor materials that generate a band structure for enhanced charge generation and transport.

[0026] The semiconductor structures maybe inorganic, and the multi-layered semiconductor structure can further include organic charge-transport layers between the inorganic semiconductor layers to improve charge-collection efficiency.

[0027] The multi-layered semiconductor structure may also include structures to achieve effects such as transistor amplification, phototransistor amplification, avalanche multiplication, photoconductive gain, semiconductor optical amplification, heterojunction improvement of carrier injection and separation, quantum-well increase in optical gain, plasmonic enhancement, multiple exciton generation, hot carrier effects for signal amplification, trap-assisted photoconductive gain, optical feedback, high-mobility-material enhancement of charge-collection efficiency and reduced noise, or stimulated emission in quantum cascade structures to extend the detector's sensitivity range and amplify low-energy radiation.

[0028] A method of enhancing radiation detection performance in a radiation-sensitive device can utilize the above-described radiation-sensitive device. The radiationsensitive device is exposed to incident radiation. An electric field is applied to the composite semiconductor structure via the plurality of electrodes. An intrinsic chargeamplification effect is generated within the composite semiconductor structure, which includes causing charge carriers created by the incident radiation in at least one of the semiconductor structures to induce the generation of additional charge carriers within the composite semiconductor structure, thereby enhancing a signal-to-noise ratio of the radiation-sensitive device.

[0029] The multi-layered semiconductor structure in the method may specifically include amorphous selenium and cesium lead bromide perovskite layers.Attorney Docket No. cap-oi6pct

[0030] The method can also involve generating an intrinsic charge-amplification effect using the blocking or charge-transport layers to increase the sensitivity of the device.

[0031] This device and method can regulate dark-current noise to improve radiation detection with increased sensitivity and reduced noise characteristics.

[0032] BRIEF DESCRIPTION OF THE DRAWINGS FIG. i is a side-sectional view of a multi-layered semiconductor radiation detector io with semiconducting charge-transport layers (14) at both electrodes (12, 20) along with dual semiconductor layers (16', 16") and an interfacial layer (18).

[0033] FIG. 2 is a side-sectional view of a composite semiconductor structure (10) with inorganic / organic semiconductor particles (16") dispersed within an organic semiconductor matrix (16'), sandwiched between the charge-transport layers (14).

[0034] FIG. 3 is a side-sectional view of a composite semiconductor structure (10) comprising a gradient semiconducting structure that transitions from, for example, an a-Se-rich region (16') to a CsPbBr3-rich region (16").

[0035] FIG. 4 is a side-sectional view of a structure (10) that incorporates three distinct semiconductor layers— e.g., a ZnO hole-blocking layer (16”) that is also sensitive to radiation, a MAPbI3primary detection layer (16’), and a GaN hole transport layer (16”’).

[0036] FIG. 5 is a side-sectional view of a device (10) that incorporates semiconductor (e.g., a-Se, CsPbBr3) or wavelength-matched nanoparticles (16") dispersed within a CsPbBr3semiconductor matrix (16').

[0037] FIG. 6 is a side-sectional view of a device (10) featuring semiconductor quantum dots (16') (PbS QDs) in a polymer matrix atop a bulk semiconductor layer (16").

[0038] FIG. 7 is a side-sectional view of a structure that incorporates a semiconductor layer of multiple exciton generation (MEG) capable quantum dots (16') (e.g., CsPbBr3or FAPbI3) with another semiconductor layer (16").

[0039] FIG. 8 is a side-sectional view of a device (10) that combines an organic semiconductor layer (16') with an inorganic semiconductor layer (16").

[0040] FIG. 9 is a side-sectional view of a superlattice semiconductor structure (10) with alternating layers of different semiconductors (16' and 16") (e.g., CsPbBr3and TiO2).

[0041] FIG. 10 is a side-sectional view of a composite ceramic semiconductor structure (10) with PbS nanoparticles (16") dispersed in a BaTiO3matrix (16') atop a BaTiO3semiconductor layer (16"').

[0042] FIG. 11 is a side-sectional view of a composite ceramic semiconductor structure (10) with a 2D-material semiconductor charge-transport layer (16') (e.g., M0S2, graphene, or PEA2PbBr4) with a bulk semiconductor layer (16").

[0043] FIG. 12 is a side-sectional view of a field-effect transistor structure (10) where the semiconductor sensor (16) (e.g., CsPbBr3or graphene) functions as part of a gated channel into which a pattern of source and drain electrodes (12, 20) are interdigitated.Attorney Docket No. cap-oi6pct

[0044] FIG. 13 is a side-sectional view of a device (10) that incorporates optical structures (28), such as distributed Bragg reflectors or whispering-gallery-mode cavities with an inorganic semiconductor layer (16).

[0045] FIG. 14 is a side-sectional view of a device that features a semiconductor phototransistor layer (16) with an interdigitated electrode (20) for signal readout and optical reflector structures (24).

[0046] In the accompanying drawings, like reference characters refer to the same or similar parts throughout the different views, and apostrophes are used to differentiate multiple instances of the same item or different embodiments of items sharing the same reference numeral. The drawings are not necessarily to scale; instead, an emphasis is placed on illustrating particular principles in the exemplifications discussed below. For any drawings that include text (words, reference characters, and / or numbers), alternative versions of the drawings without the text are to be understood as being part of this disclosure; and formal replacement drawings without such text may be substituted therefor.

[0047] DETAILED DESCRIPTION

[0048] The foregoing and other features and advantages of various aspects of the invention(s) will be apparent from the following more particular description of various concepts and specific implementations within the broader bounds of the invention(s). Various aspects of the subject matter introduced above and discussed in greater detail below may be implemented in any of numerous ways, as the subject matter is not limited to any particular manner of implementation. Examples of specific implementations and applications are provided primarily for illustrative purposes.

[0049] Unless otherwise herein defined, used, or characterized, terms that are used herein (including technical and scientific terms) are to be interpreted as having a meaning that is consistent with their accepted meaning in the context of the relevant art and are not to be interpreted in an idealized or overly formal sense unless expressly so defined herein. For example, if a particular composition is referenced, the composition may be substantially (though not perfectly) pure, as practical and imperfect realities may apply; e.g., the potential presence of at least trace impurities _e.g., at less than 1 or 2%) can be understood as being within the scope of the description. Likewise, if a particular shape is referenced, the shape is intended to include imperfect variations from ideal shapes, e.g., due to manufacturing tolerances. Percentages or concentrations expressed herein can be in terms of weight or volume.

[0050] Although the terms, first, second, third, etc., maybe used herein to describe various elements, these elements are not to be limited by these terms. These terms are simply used to distinguish one element from another. Thus, a first element, discussedAttorney Docket No. cap-oi6pct

[0051] below, could be termed a second element without departing from the teachings of the exemplary implementations.

[0052] Spatially relative terms, such as “above,” “below,” “left,” “right,” “in front,” and “behind,” may be used herein for ease of description to describe the relationship of one element to another element, as illustrated in the figures. It will be understood that the spatially relative terms, as well as the illustrated configurations, are intended to encompass different orientations of the apparatus in use or operation in addition to the orientations described herein and depicted in the figures. For example, if the apparatus in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “above” may encompass both an orientation of above and below. The apparatus maybe otherwise oriented (e.g., rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein should be interpreted accordingly. The term “about” can mean within ± 10% of the value recited. In addition, where a range of values is provided, each subrange and each individual value between the upper and lower ends of the range is contemplated and, therefore, disclosed.

[0053] Further still, in this disclosure, when an element is referred to as being “on,” “connected to,” “coupled to,” “in contact with,” etc., another element, it may be directly on, connected to, coupled to, or in contact with the other element or intervening elements may be present unless otherwise specified.

[0054] Some of the terminology used herein is associated with particular implementations and is not intended to limit more generic exemplifications of the invention. As used herein, singular forms, such as those introduced with the articles, “a” and “an,” are intended to include the plural forms as well, unless the context indicates otherwise. Additionally, the terms “includes,” “including,” “comprises,” and “comprising” specify the presence of the stated elements or steps but do not preclude the presence or addition of one or more other elements or steps.

[0055] Introduction:

[0056] This disclosure describes a radiation-sensitive device that includes a multilayered semiconductor structure designed to enhance radiation detection with increased sensitivity and reduced noise characteristics. This structure can comprise various semiconductor layers, including blocking or charge-transport layers that may generate charge carriers from incoming radiation and regulate dark-current noise. A semiconductor, as that term is used herein, is a material with an ~ <5 eV bandgap, though a material may be semiconducting, semi-insulating, or insulating depending on its thick or doping or based on external factors, such as temperature, electric fields, etc. Typical ambient temperatures and electrical field levels can be assumed unless otherwise indicated. Semiconductor materials that are particularly suited for this deviceAttorney Docket No. cap-oi6pct

[0057] and the applications described herein include those that have a high sensitivity to electromagnetic radiation, such as X-ray radiation, and high intrinsic resistivity.

[0058] The device can incorporate a combination of amorphous selenium (a-Se) and cesium lead bromide perovskite (CsPbBr3) layers of different thicknesses in a range from 1 angstrom to 10 microns, which can act as blocking or charge-transport layers to enhance charge propagation under an electric field generated by the charged electrodes. This configuration also generates an intrinsic charge-amplification effect, increasing the sensitivity of the detectors.

[0059] The device may also include a scintillator material to convert incoming radiation to visible light for detection, further enhancing radiation detection performance.

[0060] Suitable scintillator materials include those that have a high sensitivity to electromagnetic radiation, e.g., X-ray radiation, and wavelength-matching with the semiconductor photodetection wavelengths. An X-ray sensitive scintillator is incorporated into an X-ray-sensitive semiconductor, with the scintillator emitting photons at energies equal to or exceeding the semiconductor's bandgap energy. This arrangement offers dual benefits: X-rays generate signals in both the scintillator and semiconductor materials, while the scintillator's light produces a signal in the semiconductor that largely circumvents the trapping effects typically caused by semiconductor defects. These defects generally become more pronounced as charge propagation distance increases. The end result is an amplified signal that behaves as if it were generated by a trap-free semiconductor, potentially enhancing overall detector performance. The multi-layered semiconductor structure may be part of an X-ray flat panel radiation detector device that can detect X-ray radiation effectively. The integration of these components and materials may result in a system that exhibits enhanced performance in radiation detection and that mitigates common limitations in x-ray detection systems, making it suitable for various applications.

[0061] The radiation-sensitive device may comprise a multi-layered semiconductor structure including semiconductor layers and blocking layers or charge-transport layers. These layers may be designed to enhance charge propagation under an electric field and to generate charge carriers from incoming radiation. The device may also incorporate a scintillator material that can convert incoming radiation to visible light for detection, thereby enhancing radiation detection performance.

[0062] The multi-layered semiconductor structure may be exposed to incident radiation, which can generate charge carriers and enhance charge propagation, leading to increased sensitivity and reduced noise characteristics. Nanostructures may be included in a matrix of semiconductor materials to create localized charge-amplification sites, further enhancing radiation detection. The device may regulate dark-current noise, which can contribute to the enhanced performance of radiation detection. TheAttorney Docket No. cap-oi6pct

[0063] quantum-engineered semiconductor radiation-sensitive devices may exhibit enhanced performance due to the multi-semiconductor and multi-semiconductor-scintillator structure, which may include an electric field to enhance charge propagation and generate charge carriers. The blocking layers or charge-transport layers may act to enhance charge propagation and generate charge carriers, contributing to the overall enhanced performance of the device.

[0064] The composite semiconductor structure at the core of the radiation detector design can contribute significantly to the device's enhanced performance through several key mechanisms, which are discussed below.

[0065] First, the layered architecture enables distributed charge generation throughout the device structure. When radiation interacts with different semiconductor layers, electron-hole pairs are generated at multiple depths. This distributed interaction maximizes the detection probability and efficiency of incoming radiation photons, significantly improving sensitivity compared to single-semiconductor designs.

[0066] Second, the strategic combination of different semiconductor materials can create an optimized balance between high sensitivity and low dark current, which are typically competing parameters in conventional detectors. For example, in FIG.5, the combination of wavelength-matched scintillator nanoparticles in a CsPbBr3matrix creates a dual-signal generation mechanism, including direct charge creation from radiation absorption and secondary charge generation when scintillation photons are absorbed by the surrounding semiconductor. This intrinsic charge amplification increases sensitivity without corresponding increases in dark current.

[0067] Third, the composite structure allows for sophisticated band engineering across interfaces. As illustrated in FIG. 4 with its three-layer structure (ZnO / MAPbls / GaN), the energy band alignment creates selective transport pathways where radiationgenerated carriers are efficiently collected while thermally generated carriers (dark current) are suppressed by potential barriers. This selective transport mechanism improves the signal-to-noise ratio.

[0068] Fourth, the configurations shown in FIG. 9 (superlattice structure) and FIG. 12 (transistor configuration) introduce built-in signal amplification. The transistor structure is particularly effective, as small changes in radiation-induced charge dramatically modulate the channel conductivity, providing quantum-level signal amplification without external electronics. The interdigitated electrode design further reduces carrier transit distance, minimizing recombination losses.

[0069] Another advantage of the composite detector lies in its tunable depth profiling for energy-discriminating applications. Because different materials and thicknesses can be stacked, each semiconductor structure can be made sensitive to specific energy bands. This is particularly useful when performing spectral imaging or dual-energy X-Attorney Docket No. cap-oi6pct

[0070] ray detection, as separate semiconductors can absorb different photon energies while preserving high overall sensitivity.

[0071] Finally, having multiple functional semiconductor structures makes it possible to integrate other electronic elements— such as embedded readout circuits, photonic waveguides, or plasmonic structures— within the same stack. These elements can further boost detector gain, increase bandwidth, or even enable advanced functionalities such as real-time signal processing directly within the detector, paving the way for more compact and high-performance radiation detection systems.

[0072] In traditional detectors, layers are typically specialized for either charge generation upon interacting with incoming radiation or transport of charges under an applied electric field. This dual functionality creates amplification as charges generated in one semiconductor structure trigger additional charge generation in adjacent semiconductor structures by impact ionization or avalanche multiplication as they transit through the device. Dual-phase semiconductor structures can be designed to create high electric fields, especially at interfaces or within specific phases, promoting the impact ionization process. In some dual-structure designs, particularly those with atomically thin layers, the charge carriers can be confined in a two-dimensional plane. This confinement can increase carrier interaction, potentially enhancing the impact ionization efficiency. Dual-phase structures involving different semiconductor materials (hetero structures) can be engineered to manipulate carrier energies and to enhance the impact ionization process in one or both phases.

[0073] The heterojunctions between different semiconductor structures create built-in electric fields of io4-io5V / cm at interfaces without requiring any excessive external bias voltage. These localized high-field regions serve dual purposes: they efficiently separate electron-hole pairs (reducing recombination losses by 6o-8o% compared to homogeneous materials) while accelerating charge carriers to energies sufficient to trigger impact ionization. In optimized CsPbBrs / a-Se interfaces, the band offset of approximately 0.7-0.9 eV creates an energy step that preferentially accelerates electrons while blocking holes, resulting in directional charge transport with minimal reverse leakage. This interface engineering reduces dark current to <io-9A / cm2while gaining high radiation sensitivity.

[0074] Figure 12 demonstrates the most powerful intrinsic amplification mechanism: integrating the detector within a field-effect transistor structure. Here, radiationgenerated charges in the semiconductor layer modulate the conductivity of the channel between the interdigitated source-drain electrodes. This transistor action provides significant gain, as a small number of radiation-generated charges control a much larger current flowing through the channel, effectively creating built-in signal amplification directly within the detection element itself.Attorney Docket No. cap-oi6pct

[0075] Strategic incorporation of specific defect states at semiconductor interfaces could create energy "stepping stones" within the bandgap. These states might enable a controlled avalanche effect where carriers gain energy in shorter steps through these intermediary levels, triggering the release of additional carriers at each step without requiring the high fields that cause noise in traditional avalanche detectors.

[0076] Exemplifications:

[0077] Exemplary embodiments of the device (10) are shown in FIGS. 1-14, though these designs are not limited to the specified materials. Each of these devices can be prepared on various types of active pixel arrays or substrates of different materials, such as amorphous silicon thin-film transistor (TFT), silicon complementary metal-oxide semiconductor (CMOS) TFT, indium gallium zinc oxide (IGZO) TFT, flexible or glass TFT, etc.

[0078] A multi-layered semiconductor radiation detector (10) with charge transport layers (14) at both electrodes (12, 20), dual semiconductor layers (16', 16"), and an interfacial layer (18) is shown in FIG. 1. When radiation strikes the device, it generates electron-hole pairs in both semiconductor layers (16', 16"). The charged electrodes (12, 20) apply an electric field across the semiconductor layers that causes these charge carriers to migrate toward their respective attracting electrodes (12, 20). The interfacial layer (18) serves to optimize band alignment between the semiconductors, reducing recombination losses while facilitating charge transfer. This layered structure enables more efficient charge collection and charge amplification compared to single-layer detectors, while the spatial separation of functions (z.e., charge generation, transport, and blocking) allows for optimization of each layer independently, resulting in an improved signal-to-noise ratio.

[0079] The device (10) of FIG. 2 is a composite semiconductor layer (16’, 16”) with inorganic / organic semiconductor particles dispersed within an organic semiconductor matrix, sandwiched between charge transport layers (14). During operation, incident radiation interacts with both the matrix and dispersed materials, creating electron-hole pairs throughout the composite. The dispersed material may have higher atomic number elements that enhance radiation absorption or that may increase the layer resistivity to become semi-insulating and also radiation-sensitive, while the matrix facilitates charge transport. This structure creates localized charge generation sites that contribute to the overall signal while maintaining low dark-current characteristics. The composite approach enables combining complementary material properties that would be difficult to achieve with a single semiconductor.

[0080] The device (10) of FIG. 3 features a gradient semiconducting structure transitioning from, for example, an a-Se-rich region (16') to a CsPbBr3-rich region (16"). When radiation interacts with this gradient structure, different energy photons areAttorney Docket No. cap-oi6pct

[0081] preferentially absorbed at different depths. The continuous transition between materials eliminates sharp heterojunctions that typically act as recombination centers. Charge carriers generated by radiation can move more freely through the gradient, while thermally generated dark-current carriers are impeded by the band structure engineering. This approach provides enhanced charge-transport properties while maintaining high absorption efficiency across a wider energy spectrum, making it suitable for spectral radiation detection applications.

[0082] The structure (io) of FIG. 4 incorporates three distinct semiconductor layers, for example, a ZnO hole-blocking layer (16”), which is also sensitive to radiation, a MAPbI3primary detection layer (16’), and a GaN hole-transport layer (16”’). During operation, radiation creates electron-hole pairs primarily in the MAPbI3layer (16’). The energy band alignment of these materials creates a selective transport system— electrons move efficiently toward the top electrode (12) through the ZnO layer (16”), which blocks holes, while holes move toward the bottom electrode (20) through the GaN layer (16’”). This energy-band engineering allows radiation-generated carriers to be efficiently collected while thermally generated carriers (dark current) are suppressed. This selective-transport mechanism significantly improves the signal-to-noise ratio compared to single-layer detectors.

[0083] The device (10) of FIG. 5 incorporates semiconductor (e.g., a-Se, CsPbBr3) particles 16” or wavelength-matched nanoparticles [e.g., Gd3Al2GaOi2(GAGG) nanoparticles emitting at 520-560 nm, Y3A150I2(YAG) nanoparticles emitting at 530-56 nm, CsI nanoparticles emitting at around 550 nm, Tb3+-doped nanophosphores (e.g., Gd202S or Y2O3) emitting at around 545 nm, and / or green-emitting quantum dots (formed of, e.g., CdSe / ZnS, InP / ZnS, and / or CsPbBrs) tunable to 500-550 nm] dispersed within a CsPbBr3semiconductor matrix (16’). When radiation interacts with this composite, it generates electron-hole pairs (or photons) in both materials. The nanoparticles, with their high atomic number and high radiation sensitivity or high resistivity, efficiently absorb X-rays and generate charge carriers (or photons), while the surrounding CsPbBr3matrix provides efficient charge generation and transport pathways. In the case of generated photons, these photons, themselves, produce charge from the surrounding semiconductor. Energy-transfer processes, such as Forster resonance energy transfer (FRET), will also occur in this example. The interface between these materials creates a band alignment that facilitates charge transfer from a-Se to CsPbBr3, effectively amplifying the signal. This mechanism provides an intrinsic charge amplification effect without increasing dark current, as the charge-blocking properties at material interfaces impede thermally generated carriers but allow radiation-generated carriers to pass.Attorney Docket No. cap-oi6pct

[0084] The device (io) of FIG. 6 features a quantum dot (PbS QDs) semiconductor layer (16') in a polymer matrix atop a bulk semiconductor layer (16"). The quantum dots, with their size-tunable bandgap, can be engineered to absorb specific radiation energies efficiently. When radiation strikes the device, the quantum confinement effect in the QDs enhances absorption cross-sections and can enable multiple electron-hole pair generation from a single photon. The charge carriers generated in the QDs transfer to the bulk-semiconductor layer (16") for collection by, e.g., Forster resonance energy transfer (FRET). The polymer matrix provides mechanical stability while maintaining electronic isolation between dots to preserve quantum effects. This quantum-engineered structure offers enhanced detection efficiency for specific radiation energies while maintaining compatibility with large-area fabrication processes.

[0085] The structure (io) of FIG. 7 incorporates a layer of multiple exciton generation (MEG) capable quantum dots (CsPbls or FAPbb-,) (16’) with a semiconductor layer (16”). During operation, high-energy radiation (with energy exceeding 2-3 times the bandgap) interacting with these specialized quantum dots can generate multiple electron-hole pairs per photon through impact -ionization processes. This physical phenomenon effectively multiplies the charge carriers generated per radiation interaction event. The scientific significance lies in circumventing the traditional quantum efficiency limitations of conventional detectors. This approach is particularly valuable for high-energy-radiation detection, where the excess energy of photons can be harvested more efficiently, enabling radiation-dose reduction in applications such as medical imaging or other imaging applications, wherein the semiconductor layers (16’, 16”) form a photodetector array.

[0086] The device (10) of FIG. 8 combines an organic semiconductor layer (16') with an inorganic semiconductor layer (16"). When radiation interacts with the device, the inorganic layer (with typically higher atomic number elements) efficiently absorbs the radiation and generates primary charge carriers. The organic semiconductor layer (16’) may function as a charge-transport layer with potentially higher carrier mobility for certain carrier types (holes or electrons). The heterojunction between these dissimilar materials creates an energy band alignment that facilitates charge separation, reducing recombination losses. This structure leverages the complementaiy properties of both material classes— the high radiation-stopping power of inorganics and the solutionprocessability, high radiation sensitivity, and flexibility of organics— enabling potentially lower-cost, large-area detector production.

[0087] The device (10) of FIG. 9 has a superlattice semiconductor structure with alternating thin layers of different semiconductors [CsPbBr3(16’) andTiO2(16”)].

[0088] When radiation interacts with this structure, the periodic potential created by the alternating materials modifies the electronic band structure, creating minibands andAttorney Docket No. cap-oi6pct

[0089] band offsets that can be engineered to optimize charge separation and transport. Each interface acts as a heterojunction that can facilitate charge separation. The superlattice structure also creates quantum confinement effects when layer thicknesses approach the nanoscale, potentially enhancing radiation interaction and amplification crosssections. This design enables precise electronic structure engineering that can be optimized for specific radiation energies and detector performance parameters.

[0090] A superlattice structure to of alternating thin semiconductor layers can achieve intrinsic signal amplification through the precise engineering of quantum confinement effects. A superlattice, as depicted in FIG. 9, is an artificial periodic structure formed by alternating thin layers of at least two different semiconductor materials (16' and 16"). The "engineering" of this structure is achieved by controlling the material composition and, critically, the thickness of these alternating layers during fabrication, often using advanced epitaxial growth techniques. When the thickness of the layers is reduced to the nanometer scale, comparable to or smaller than the de Broglie wavelength of the charge carriers, the carriers become spatially confined in one dimension. This phenomenon is known as the quantum confinement effect. In an isolated quantum well, this confinement results in discrete, quantized energy levels. However, in a superlattice, the barriers between the wells are thin enough to allow the quantum mechanical wave functions of carriers in adjacent wells to overlap and couple. This coupling causes the discrete energy levels to broaden into a series of allowed energy bands known as "minibands," separated by forbidden gaps.

[0091] The width, position, and curvature of these minibands are not fixed properties of the bulk materials but are instead determined by the engineered parameters of the superlattice, namely the well and barrier thicknesses and material compositions. This band-structure engineering is specifically designed to enhance impact ionization for one type of charge carrier while suppressing it for the other. For instance, the superlattice can be engineered to create a wide, continuous-like lowest conduction miniband, which allows electrons to be easily accelerated by an applied electric field and gain sufficient kinetic energy to initiate impact ionization. Simultaneously, the valence band can be engineered to form flat, narrow minibands that are substantially separated in energy.

[0092] This structure hinders the acceleration of holes, effectively increasing their ionization threshold energy and suppressing hole-initiated impact ionization. The result is a highly asymmetric ionization process dominated by a single carrier type (e.g., electrons). An electron accelerated by the field collides with the lattice, creating a secondary electron-hole pair in an impact ionization event. This process cascades, leading to a controlled avalanche multiplication. By engineering the superlattice to favor a single-carrier ionization process, the randomness and statistical fluctuationsAttorney Docket No. cap-oi6pct

[0093] inherent in dual-carrier avalanche are minimized, leading to a low-noise amplification of the initial radiation-generated signal.

[0094] The device (10) of FIG. 10 has a composite ceramic semiconductor structure with PbS nanoparticles (16”) dispersed in a BaTiO3matrix (16’) atop a ceramic semiconductor layer (16”’) formed of BaTiO3. When radiation interacts with this composite, the high-Z PbS nanoparticles (16”), with their large radiation cross-section, efficiently absorb radiation and generate charge carriers. The BaTiO3ceramic matrix (16’) provides structural stability and potentially piezoelectric properties that can enhance charge separation and collection. The interfaces between the nanoparticles (16”) and matrix (16’) create energy barriers that may reduce dark current while allowing radiation-generated carriers to be collected. This structure combines high radiation sensitivity with the environmental stability and thermal resistance of ceramic materials, addressing challenges in detector longevity in harsh operating environments.

[0095] The device (10) of FIG. 11 incorporates a 2D-material semiconductor chargetransport layer (16”) e.g., including as a 2D material any of M0S2, graphene, or PEAaPbBr4) with a bulk semiconductor layer (16'). During operation, radiation generates charge carriers primarily in the bulk semiconductor (16'). The 2D-material layer (16”), with its atomically thin structure, exhibits distinctive electronic properties, including potentially high in-plane carrier mobility and a tunable band structure. This helps extract charge carriers from the bulk semiconductor efficiently, reducing the transit time and, thus, recombination losses. The 2D material’s inherent quantum confinement in one dimension creates unique electronic states that can be engineered to facilitate specific carrier types (electrons or holes) transport while blocking others, enhancing collection efficiency while minimizing dark current.

[0096] In configurations, such as those illustrated in FIGS. 10 and 11, where a second semiconductor composition is dispersed in a first semiconductor matrix, this dispersion functions differently from discrete layers but achieves similar goals through alternative mechanisms. While discrete layers create well-defined interfaces where band alignments and charge barriers occur predictably along planar boundaries, a dispersion creates a three-dimensional network of semiconductor-semiconductor interfaces throughout the volume of the material.

[0097] This dispersed configuration offers several unique advantages. First, it dramatically increases the total interfacial area between the two semiconductors compared to planar layers, providing more opportunities for beneficial charge transfer, separation, and amplification effects. Second, the dispersion creates localized electric field enhancements around each dispersed particle due to differences in dielectric constants and band structures, which can improve charge separation efficiency upon radiation interaction. Third, the matrix-dispersion arrangement allows radiation toAttorney Docket No. cap-oi6pct

[0098] interact with both semiconductors simultaneously throughout the entire detection volume, whereas in layered structures, radiation is absorbed sequentially (depending on the stopping power) as it passes through each discrete layer.

[0099] From a manufacturing perspective, the dispersion approach can often be achieved through simpler solution-based processing methods, such as co-deposition or in-situ growth, compared to the precise deposition control utilized for multiple discrete layers. Additionally, the dispersed structure can maintain its beneficial multisemiconductor effects even if some dimensional variability occurs during fabrication, offering greater manufacturing tolerance compared to the critical thickness specifications of discrete layers.

[0100] Both approaches ultimately serve the core inventive concept of using multiple semiconductor materials to enhance radiation detection performance, with the dispersion method representing an alternative embodiment that accomplishes the same fundamental goals through volumetric rather than planar semiconductor interfaces.

[0101] The device (10) schematically illustrated in FIG. 12 is a field-effect transistor structure designed for radiation detection, where the semiconductor sensor (16) (e.g., CsPbBr3or graphene), which can have a thickness in a range from 1 nm to 1 cm, functions as part of a gated channel with an interdigitated pattern of source electrodes (12), gates (17), and drain electrodes (20), each of which can be formed of a different semiconductor material, that extend thereinto and serve as the electrical contacts for the device (10). These interdigitated electrodes (12, 20) reduce carrier transit distance and improve collection efficiency by enabling effective lateral charge collection across the semiconductor layer (16). The central semiconductor layer (16) lying beneath this electrode pattern (12, 20) serves as both the semiconductor sensor and the doped semiconductor substrate gate. This dual -function semiconductor layer (16) acts as the active radiation-sensing element that generates electron-hole pairs when struck by radiation while simultaneously functioning as the transistor channel / gate region where conductivity in the channel is modulated by the electric field generated by these radiation-induced charges. The semiconductor can be a radiation-sensitive material, such as perovskite compounds (CsPbBn, MAPbL), high-Z compound semiconductors (CdTe, PbS), or other radiation-sensitive materials described herein. The bottom electrode / substrate (24) provides structural support and electrical connectivity for the device. The bottom electrode / substrate (24) can be formed, e.g., of indium tin oxide, gold, platinum, or any of a variety of other electrically conductive materials.

[0102] A slice of the device (10) of FIG. 12 is illustrated in FIG. 15, which shows the bulk semiconductor sensor layer (16) with a bottom electrode (24), which also serves as the bottom substrate, on one side and a source electrode (12), a drain electrode (20) and a gate (17) atop an insulator or high-resistivity semiconductor layer (21). SemiconductorAttorney Docket No. cap-oi6pct

[0103] channels (16’) of an opposite type (p-type / n-type) from the type of the bulk semiconductor (16) are embedded in the bulk semiconductor (16) between the bulk semiconductor (16) and the source electrode (12) and drain electrode (20).

[0104] In the transistor configuration, the source electrode (12), drain electrode (16), and gate (17) can be fabricated from different semiconductor materials rather than the traditional approach of using a single semiconductor material, creating additional semiconductor interfaces throughout the device. For instance, organic semiconductors, such as highly doped organic semiconductors, such as poly(3,4-ethylenedioxythiophene) (PEDOT), or 2D semiconductor materials, such as M0S2, can form the source and drain regions, while a different semiconductor, such as CsPbBrs or CdTe, can serve as the gate and the channel material. These semiconductors also participate in the radiation detection process through charge generation. This approach creates a truly integrated multi-semiconductor system, wherein each componentchannel, source, drain, and gate— contributes to the device's radiation sensitivity while preserving the inherent amplification advantage of the transistor structure.

[0105] A multi-layer channel design can incorporate different semiconductors stacked vertically. For instance, a graphene layer may serve as a high-mobility charge transport pathway on top of a radiation-sensitive CsPbBrs layer. This arrangement allows radiation-generated charges in the perovskite to be rapidly collected through the graphene, leveraging the unique properties of each semiconductor material.

[0106] Semiconductor heterojunctions can be created laterally between the source electrode (12) and the drain electrode (16), using different materials for different parts of the channel (16’). This design enables engineering of band offsets that enhance charge separation while reducing dark current, a key advantage of multi-semiconductor structures over single-material designs.

[0107] The gate dielectric interface can incorporate semiconducting oxide layers, such as ZnO or Ti02, between the channel (16’) and gate electrode (17), serving dual purposes as both dielectric and radiation-sensitive layers. These additional semiconductor interfaces contribute to the overall radiation response while maintaining the transistor's field-effect functionality.

[0108] Quantum dot or nanocrystal semiconductors of one material can be embedded within a matrix of another semiconductor material in the channels (16’), creating multiple semiconductor interfaces that enhance radiation sensitivity through quantum confinement effects while preserving the transistor's amplification capabilities.

[0109] This transduction mechanism converts the radiation signal directly into an amplified current signal between the source and drain electrodes (12, 20). Unlike conventional detectors that simply collect radiation-generated charges, this active design leverages the intrinsic gain mechanism of transistors, where small changes inAttorney Docket No. cap-oi6pct

[0110] gate charge can control much larger source-drain currents. What makes this design particularly effective is its intrinsic amplification mechanism— small changes in charge carrier concentration from radiation interactions causing much larger changes in the source-drain current, significantly enhancing detection sensitivity while maintaining favorable noise characteristics compared to conventional radiation detectors.

[0111] Accordingly, this active design provides built-in quantum signal amplification, potentially enabling the detection of very low radiation intensities.

[0112] The device (10) of FIG. 13 incorporates optical structures (28), such as distributed Bragg reflectors or whispering-gallery-mode cavities, with an inorganic semiconductor layer (16). During radiation detection, high-energy photons interact with the semiconductor (16) to generate both charge carriers and secondary photons through scintillation effects. The optical structures create resonant cavities that enhance lightmatter interactions, potentially enabling stimulated emission processes that amplify the optical signal. These optical structures (28) effectively increase the path length of secondary photons within the active material, enhancing the probability of their conversion to charge carriers. This approach creates an internal optical amplification mechanism that increases detector sensitivity while maintaining the low dark-current characteristics of the semiconductor material.

[0113] More specifically, embodiments with integrated optical structures e.g., as shown in FIG. 13) create an internal optical feedback mechanism, thereby amplifying the detected signal. An exemplary implementation of these optical structures (28) is a pair of Distributed Bragg Reflectors (DBRs) positioned above and below the active semiconductor layer (16) to form an optical microcavity, also known as a Fabry-Perot resonator. A DBR is a one-dimensional photonic crystal constructed from a periodic stack of alternating thin-film layers of two or more dielectric materials with different refractive indices. The thickness of each layer is precisely controlled, typically to be one-quarter of the target wavelength of light within that material.

[0114] This configuration is designed so that the small reflections from each interface within the stack interfere constructively for a specific range of wavelengths, known as the "photonic stopband". For wavelengths within this stopband, the DBR functions as a highly efficient mirror with reflectivity that can approach 100%, effectively "forbidding" light in this spectral range from propagating through it. The device is configured such that the active semiconductor layer is sandwiched between two such DBRs, creating the resonant optical microcavity.

[0115] The operational principle is as follows. Incident high-energy radiation is absorbed by the semiconductor layer (16), generating primary electron-hole pairs, which contribute to the electrical signal. In addition to charge carriers, this interaction can also produce lower-energy secondary photons through processes such asAttorney Docket No. cap-oi6pct

[0116] scintillation and / or radiative recombination of electron-hole pairs. The DBRs are specifically engineered so that their photonic stopband is centered on the emission wavelength of these secondary photons. Consequently, any secondary photon emitted towards the DBRs is reflected back into the semiconductor layer instead of escaping the device. This process traps the photons within the microcavity, causing them to travel back and forth through the active material multiple times. This phenomenon, known as "photon recycling," dramatically increases the effective optical path length for the secondary photons.

[0117] The increased time that the recycled photons spend within the semiconductor layer significantly enhances their probability of being re-absorbed. Each re-absorbed photon generates a new electron-hole pair, adding to the total collected charge. This configuration effectively creates an optical-to-electrical feedback loop within the detector itself. Secondary photons that would otherwise be lost are efficiently recycled to generate additional charge carriers, resulting in an intrinsic amplification of the primaiy signal and enhancing the overall quantum efficiency of the device.

[0118] For the device (io) of FIG. 13 (optical feedback design), the inorganic semiconductor layer (16) serves as the primary radiation detection medium, while the optical structures (Bragg reflectors) (28) typically incorporate alternating layers of semiconductor materials with different refractive indices (e.g., Si / SiO2 or GaAs / AlGaAs). This multi-material approach is advantageous for facilitating the resonant cavity functionality, creating a synergistic effect that enhances detection sensitivity beyond what would be possible with a single semiconductor material.

[0119] The device (10) of FIG. 14 also incorporates optical structures (28) and features a semiconductor phototransistor layer (16) with an interdigitated electrode (20) for signal readout and optical-reflector structures (26). When radiation interacts with the phototransistor semiconductor (16), it generates primary charge carriers that modulate the channel conductivity between the interdigitated electrodes (24). The optical reflector (26) enhances this process by reflecting secondary photons (from scintillation or radiative recombination) back into the active layer. The phototransistor configuration provides photoconductive gain, where a single radiation-generated carrier can contribute to current flow multiple times before recombination. The interdigitated electrode geometry reduces carrier-transit distance, improving collection efficiency. This design combines multiple amplification mechanisms— photoconductive gain, optical enhancement, and transistor action— to achieve exceptional radiation sensitivity.

[0120] For the device (10) of FIG. 14, the phototransistor semiconductor (16) forms the primary detection layer, with secondary semiconductor materials used in the substrate (24) and / or buffer layers e.g., the charge transport layers) to optimize charge transportAttorney Docket No. cap-oi6pct

[0121] properties. Additionally, the optical reflector structures (28) may incorporate additional semiconductor materials to enhance photon recycling within the active region. This layered, multi-semiconductor approach enables the multiple amplification mechanisms that provide for exceptional radiation sensitivity while maintaining controlled dark current characteristics.

[0122] Finally, the device (10) of FIG. 16 includes amorphous silicon thin-film transistor (TFT) array gate control connections to front end electronics (4 x 128 channels) (30), a TFT pixel array backplane (32), three types of semiconductors (16, 16’, and 16”), as well as a fourth semiconductor (16”’), which is not shown but is between the third semiconductor (16”’) and a top metal electrode (12). The top metal electrode (12) is positioned over the semiconductors. A high-voltage-bias wire connection (34) is attached to the top electrode (12), and a high-voltage-bias wire (36) is attached to the high-voltage-bias wire connection (34) and to a power supply. Along another side of the device are amorphous silicon array data control connections front end electronics (4 x 128 channels) (38).

[0123] Fabrication:

[0124] Fabrication of multi-layered semiconductor radiation detector structures described herein can involve several complementary techniques tailored to the specific materials and architectures. Solution-based processing methods represent one of the most versatile approaches, particularly for materials such as perovskites (CsPbBr3) and organic semiconductors. These techniques include spin coating, where precursor solutions are applied to a rotating substrate to form uniform thin films; doctor blading, which enables large-area coating by spreading solution with a fixed-height blade; and inkjet printing for precise material deposition in specific patterns. For applications requiring higher-quality films or materials not amenable to solution processing, vacuum-deposition techniques provide excellent alternatives. Thermal evaporation allows for precisely controlled deposition of materials, such as amorphous selenium (a-Se), while sputtering is particularly suitable for electrode materials. Chemical vapor deposition (CVD) and atomic layer deposition (ALD) offer exceptional control for creating high-quality 2D-material layers and ultra-thin conformal coatings, respectively.

[0125] The nanocomposite structures featured in several designs can be fabricated via various methods, including in-situ synthesis, where nanoparticles are grown directly within a matrix material; blending pre-synthesized nanoparticles with matrix materials before deposition; or layer-by-layer assembly for more complex nanostructured films. Gradient compositions shown in some designs can be achieved through co-evaporation with gradually changing evaporation rates, controlled interdiffusion of stacked layers, or continuous flow processing with varying precursor concentrations. The superlatticeAttorney Docket No. cap-oi6pct

[0126] structures with alternating thin layers are typically formed using more sophisticated techniques, such as molecular beam epitaxy (MBE) or sequential layer deposition systems that can achieve precise control at the nanometer or even atomic scale.

[0127] The complete device fabrication process generally begins with substrate preparation, involving thorough cleaning of unpatterned or patterned glass, silicon, indium gallium zinc oxide (IGZO), or flexible substrates followed by deposition of the bottom electrode layer. The active layers are then deposited sequentially using the appropriate techniques for each material, with careful consideration of solvent compatibility and processing temperature requirements to preserve the integrity of underlying layers. Interface engineering between layers often involves specialized treatments, such as plasma cleaning or the introduction of ultra-thin buffer layers. The fabrication sequence concludes with top electrode deposition through shadow mask evaporation or photolithography techniques, followed by protective encapsulation using materials, such as parylene-C, to shield sensitive device components from environmental degradation. For commercialization, these laboratory-scale processes can be adapted for large-scale production, potentially leveraging roll-to-roll processing for flexible substrates or industrial-scale vacuum systems for rigid detector panels, with the specific manufacturing route determined by material compatibility, precision requirements, cost considerations, and the intended application.

[0128] Semiconductor materials:

[0129] The semiconductor materials in the device may include a variety of options, including those listed below. The semiconductor materials may be composed of a variety of options, including organic, inorganic, organic-inorganic hybrid, single crystalline, polycrystalline, amorphous, ceramic, or organic semiconductors, or semiinsulators. These materials may form the structure of the device, providing a diverse range of semiconductor options for construction. Examples of suitable elemental semiconductors may include silicon (Si), germanium (Ge), diamond (C with a facecentered cubic crystal structure), a-tin (a-Sn), and / or black phosphorous (P).

[0130] Examples of suitable compound semiconductors may include (i) III-V compounds, such as gallium arsenide (GaAs), indium antimonide (InSb), gallium nitride (GaN), aluminum nitride (A1N), boron nitride (BN), aluminum gallium arsenide (AlGaAs), indium gallium arsenide (InGaAs), gallium phosphide (GaP), and / or indium arsenide (InAs); (ii) II-VI compounds, such as cadmium telluride (CdTe), zinc selenide (ZnSe), zinc sulfide (ZnS), mercury cadmium telluride (HgCdTe), and / or zinc cadmium telluride (ZnCdTe); and / or (iii) IV-IV compounds, such as silicon carbide (SiC) and / or silicon germanium (SiGe).Attorney Docket No. cap-oi6pct

[0131] Examples of suitable oxide semiconductors may include zinc oxide (ZnO), titanium dioxide (Ti02), copper oxide (CuO, Cu20), tin oxide (SnO2), indium tin oxide (ITO), gallium oxide (Ga2O3), and / or indium gallium zinc oxide (IGZO).

[0132] Examples of suitable organic semiconductors may include pentacene, rubrene, poly(3-hexylthiophene) (P3HT), phenyl-Cei-butyric acid methyl ester (PCBM), and / or poly(p-phenylene vinylene) (PPV).

[0133] Examples of suitable perovskite semiconductors may include methylammonium lead iodide (CH3NH3Pbl3), formamidinium lead iodide (HC(NH2)2PbI3), cesium lead bromide (CsPbBr3), and / or mixed halide perovskites.

[0134] Examples of suitable chalcogenide semiconductors may include amorphous selenium (a-Se), lead sulfide (PbS), cadmium sulfide (CdS), cadmium selenide (CdSe), copper indium gallium selenide (CIGS), copper zinc tin sulfide (CZTS), molybdenum disulfide (MoS2), and / or tungsten diselenide (WSe2).

[0135] Examples of suitable organic-inorganic hybrid semiconductors may include methylammonium lead iodide (CH3NH3PbI3), and / or phenethylammonium lead iodide (PEA2PbI4).

[0136] Examples of suitable ceramic semiconductors may include barium titanate (BaTiO3), strontium titanate (SrTiO3), and / or lead zirconate titanate (PZT).

[0137] Examples of suitable ternary and quaternary compound semiconductors can be copper indium gallium selenide (CIGS), copper zinc tin sulfide (CZTS), and / or aluminum gallium indium phosphide (AlGalnP).

[0138] Examples of the semiconductors that can be used in two-dimensional (2d) form (with single or few atomic layers) include graphene (C), molybdenum disulfide (M0S2), tungsten diselenide (WSe2), hexagonal boron nitride (h-BN), and / or black phosphorus.

[0139] Examples of the semiconductors that can be used in the form of quantum dot semiconductors may include lead sulfide (PbS), cadmium selenide (CdSe), indium arsenide (InAs), and / or graphene.

[0140] Examples of the semiconductors that can be used in amorphous form may include amorphous silicon (a-Si), amorphous indium gallium zinc oxide (a-IGZO), and / or amorphous selenium (a-Se).

[0141] Examples of the semiconductors that can serve as wide-bandgap semiconductors may include aluminum nitride, aluminum nitride, boron nitride, and / or diamond.

[0142] The above semiconductors are merely examples, as other semiconductors or semi-insulating materials can also or alternatively be used in the devices.

[0143] In some exemplifications, the multi-layered semiconductor structure may specifically include amorphous selenium (a-Se) and cesium lead bromide perovskite (CsPbBr3) layers.Attorney Docket No. cap-oi6pct

[0144] These semiconductors can be responsive to various types of radiation, including but not limited to electromagnetic radiation, such as gamma rays, X-rays, ultraviolet (UV) radiation, visible light, infrared (IR) radiation, terahertz radiation, and / or microwave radiation. Additionally or alternatively, the semiconductors can be responsive to particulate radiation, such as alpha particles, beta particles, neutrons, protons, and / or heavy ions. Further still, the semiconductors can alternatively or additionally be responsive to cosmic rays.

[0145] The choice of semiconductor materials in the device can be tailored to the specific type of radiation to be detected, based on factors such as atomic number, bandgap, carrier mobility, and radiation hardness, for example. The multi-layered structure allows for the combination of different materials to optimize sensitivity, noise characteristics, and overall detector performance for the intended application.

[0146] As an example, in the multi-layer configuration of the device, at least one of the semiconductor layers functions as a charge-blocking layer or as a charge-transport layer, or both simultaneously. These functional layers serve a dual purpose: firstly, they facilitate charge propagation under an applied electric field, and secondly, they generate charge carriers upon interaction with incoming radiation. This dual functionality results in an intrinsic charge-amplification effect that advantageously increases the sensitivity of the detectors while concurrently regulating the dark-current noise, thereby improving the signal-to-noise ratio of the device.

[0147] The aforementioned intrinsic charge-amplification effect can be achieved through various means within the scope of the present invention. One such method involves the incorporation of one semiconductor material into the matrix of another. For instance, in one embodiment, a-Se nanoparticles or microparticles are dispersed within a CsPbBr3polycrystalline matrix. This novel approach synergistically combines the beneficial properties of both materials, potentially enhancing charge generation and transport mechanisms while maintaining low dark-current characteristics.

[0148] Alternative methods for achieving similar effects are also contemplated within the scope of the present invention. These methods may include, but are not limited to: (1) implementing a gradient doping or mixing technique, wherein one semiconductor is progressively doped or mixed into another to create a smooth transition between layers, thereby optimizing charge transport; (2) utilizing quantum dots or other nanostructures of one material dispersed within a single crystalline, polycrystalline, amorphous, ceramic, or organic matrix of another radiation-sensing material to create localized charge-amplification sites; (3) fabricating hetero structures or superlattices composed of alternating thin layers of different semiconductors, engineered to optimize the band structure for enhanced charge generation and transport; and (4) incorporating organicAttorney Docket No. cap-oi6pct

[0149] semiconducting charge-transport layers between inorganic semiconductor layers to improve charge-collection efficiency.

[0150] X-ray-detection technology faces several critical challenges that limit performance and applications, especially in medical imaging, where patient safety is paramount. Conventional detectors often require higher X-ray doses to achieve acceptable image quality due to low sensitivity and high dark-current noise, which is problematic for minimizing patient radiation exposure. Many conventional semiconductor materials, such as amorphous selenium or silicon, have low atomic numbers, resulting in suboptimal X-ray absorption, especially at higher energies. High dark-current noise can mask weak signals from low-dose X-ray exposures, further necessitating higher doses. Large-area detectors often suffer from variations in sensitivity and noise across the detection area, leading to image artifacts and reduced diagnostic value. Many semiconductor materials degrade over time due to radiation exposure and environmental factors, requiring frequent recalibration or replacement. Increasing resolution by reducing pixel size decreases X-ray absorption efficiency per pixel, creating a conflict between high resolution and low radiation doses. These limitations often force compromises between image quality and patient safety in medical imaging, potentially leading to higher radiation exposure than ideal.

[0151] Applications:

[0152] The various approaches disclosed herein can aim to optimize the balance between high sensitivity to incoming radiation and low dark current, thereby addressing key challenges in the field of radiation detection. The improved devices resulting from this invention have potential applications in diverse fields including, but not limited to, medical imaging, security screening, and scientific instrumentation. These advances in materials science and device engineering offer promising avenues for next-generation detectors that can achieve high sensitivity, low noise, uniform large-area performance, and long-term stability. Such improvements can enhance image quality while significantly reducing X-ray doses, advancing patient safety, and expanding X-ray technology applications across various fields.

[0153] In describing implementations herein, specific terminology is used for the sake of clarity. For the purpose of description, specific terms are intended to at least include technical and functional equivalents that operate in a similar manner to accomplish a similar result. Additionally, in some instances where a particular implementation includes a plurality of system elements or method steps, those elements or steps may be replaced with a single element or step. Likewise, a single element or step may be replaced with a plurality of elements or steps that serve the same purpose. Further, where parameters for various properties or other values are specified herein forAttorney Docket No. cap-oi6pct

[0154] implementations, those parameters or values can be adjusted up or down by i / iooth, 1 / 50*, 1 / 20*, i / ioth, 1 / 5*, i / 3rd, 1 / 2, 2 / 3rd, 3 / 4*, 475th, 9 / ioth, 19 / 20*, 49 / 50*, 99 / 100*, etc. (or up by a factor of 1, 2, 3, 4, 5, 6, 8, 10, 20, 50, 100, etc.), or by rounded-off approximations thereof or within a range of the specified parameter up to or down to any of the variations specified above (e.g., for a specified parameter of 100 and a variation of 1 / 100th, the value of the parameter may be in a range from 0.99 to 1.01), unless otherwise specified. Further still, where methods are recited and where steps / stages are recited in a particular order— with or without sequenced prefacing characters added for ease of reference— the steps / stages are not to be interpreted as being temporally limited to the order in which they are recited unless otherwise specified or implied by the terms and phrasing.

[0155] Additional examples consistent with the present teachings are set out in the following numbered clauses:

[0156] 1. A radiation-sensitive device, comprising:

[0157] a composite semiconductor structure comprising:

[0158] a plurality of semiconductor structures, wherein different semiconductor structures comprise different semiconductor materials, wherein the semiconductor structures are architecturally and functionally integrated such that charge carriers generated by incident radiation in one or more of the semiconductor structures cause generation of additional charge carriers within the composite semiconductor structure, thereby producing an intrinsic charge-amplification effect that enhances a signal-to-noise ratio of the radiation-sensitive device; and

[0159] a plurality of electrodes configured to apply an electric field across the composite semiconductor structure.

[0160] 2. The radiation-sensitive device of clause 1, wherein the composite semiconductor structure is integrated into a field-effect transistor (FET) architecture, wherein at least one of the semiconductor structures forms a radiation-sensitive channel, and wherein the electrodes comprise interdigitated source and drain electrodes, such that radiation-generated charge carriers in the radiation-sensitive channel modulate a current between the source and drain electrodes to produce the intrinsic charge-amplification effect.

[0161] 3. The radiation-sensitive device of clause 1 or 2, wherein the semiconductor structures form a superlattice of alternating layers, and wherein quantum confinement effects within the superlattice are engineered to enhance impact ionization, contributing to the intrinsic charge-amplification effect.

[0162] 4. The radiation-sensitive device of any of clauses 1-3, further comprising optical structures integrated with the composite semiconductor structure, wherein theAttorney Docket No. cap-oi6pct

[0163] optical structures are configured to trap and recycle secondary photons generated within the device, thereby stimulating further charge generation to produce the intrinsic charge-amplification effect.

[0164] 5. The radiation-sensitive device of any of clauses 1-4, wherein at least one of the semiconductor structures comprises quantum dots capable of multiple exciton generation (MEG), such that a single high-energy incident photon generates multiple electron-hole pairs, producing the intrinsic charge-amplification effect. 6. The radiation-sensitive device of any of clauses 1-5, wherein the semiconductor structures are in the form of distinct layers of different semiconductor materials.

[0165] 7. The radiation-sensitive device of any of clauses 1-6, wherein the semiconductor materials comprise a plurality of the following semiconductor materials:

[0166] (a) elemental semiconductors selected from silicon (Si), germanium (Ge), diamond or graphene (C), a-tin (a-Sn), or black phosphorous (P); (b) compound semiconductors selected from:

[0167] (i) III-V compounds selected from gallium arsenide (GaAs), indium antimonide (InSb), gallium nitride (GaN), aluminum nitride (A1N), boron nitride (BN), aluminum gallium arsenide (AlGaAs), indium gallium arsenide (InGaAs), gallium phosphide (GaP), or indium arsenide (InAs);

[0168] (ii) II-VI compounds selected from cadmium telluride (CdTe), zinc selenide (ZnSe), zinc sulfide (ZnS), mercury cadmium telluride (HgCdTe), or zinc cadmium telluride (ZnCdTe); or

[0169] (iii) IV-IV compounds selected from silicon carbide (SiC) or silicon germanium (SiGe);

[0170] (c) oxide semiconductors selected from zinc oxide (ZnO), titanium dioxide (Ti02), copper oxide (CuO, Cu2O), tin oxide (Sn02), indium tin oxide (ITO), gallium oxide (Ga2O3), or indium gallium zinc oxide (IGZO);

[0171] (d) organic semiconductors selected from pentacene, rubrene, poly(3- hexylthiophene) (P3HT), phenyl-Cei-butyric acid methyl ester (PCBM), or poly(p-phenylene vinylene) (PPV);

[0172] (e) perovskite semiconductors selected from methylammonium lead iodide (CH3NH3PbI3), formamidinium lead iodide (HC(NH ) Pbl3), cesium lead bromide (CsPbBr3), or mixed halide perovskites;

[0173] (f) chalcogenide semiconductors selected from amorphous selenium (a-Se), lead(II) sulfide (PbS), cadmium sulfide (CdS), copper indium gallium selenide (CIGS), or copper zinc tin sulfide (CZTS), molybdenum disulfide (MOS2), or tungsten diselenide (WSe2);Attorney Docket No. cap-oi6pct

[0174] (g) organic-inorganic hybrid semiconductors selected from methylammonium lead iodide (CH3NH3Pbl3), or phenethylammonium lead iodide (PEA2PbI4); (h) ceramic semiconductors selected from barium titanate (BaTiO3), strontium titanate (SrTiO3), or lead zirconate titanate (PZT); or

[0175] (i) ternary semiconductor aluminum gallium indium phosphide (AlGalnP). 8. The radiation-sensitive device of clause 7, wherein the semiconductor materials comprise at least one of graphene (C), molybdenum disulfide (M0S2), tungsten diselenide (WSe2), hexagonal boron nitride (h-BN), or black phosphorus in a 2D semiconductor layer.

[0176] 9. The radiation-sensitive device of clause 7 or 8, wherein the semiconductor materials comprise at least one of the following in the form of quantum dots: lead(II) sulfide (PbS), cadmium selenide (CdSe), indium arsenide (InAs), or graphene (C).

[0177] 10. The radiation-sensitive device of any of clauses 7-9, wherein the semiconductor materials comprise at least one of the following in amorphous form: amorphous silicon (a-Si), amorphous indium gallium zinc oxide (a-IGZO), or amorphous selenium (a-Se); ternary and quaternary compound semiconductors selected from copper indium gallium selenide (CIGS), copper zinc tin sulfide (CZTS), or aluminum gallium indium phosphide (AlGalnP).

[0178] 11. The radiation-sensitive device of any of clauses 7-10, wherein the multi-layered semiconductor structure comprises amorphous selenium (a-Se) and cesium lead bromide perovskite (CsPbBr3) layers.

[0179] 12. The radiation-sensitive device of any of clauses 1-11, wherein the device is an X-ray flat -panel radiation detector device.

[0180] 13. The radiation-sensitive device of any of clauses 1-12, further comprising a scintillator material incorporated into the composite semiconductor structure. 14. The radiation-sensitive device of clause 13, wherein the scintillator material is selected from the following compositions: cesium iodide (CsI), sodium iodide (Nal), bismuth germanate (BGO), lutetium oxyorthosilicate (LSO), gadolinium oxyorthosilicate (GSO), or a combination thereof.

[0181] 15. The radiation-sensitive device of clause 13 or 14, wherein the scintillator material is in the form of a layer disposed on top of or between the semiconductor structures.

[0182] 16. The radiation-sensitive device of clause 13 or 14, wherein the scintillator material is embedded within one or more of the semiconductor structures.

[0183] 17. The radiation-sensitive device of any of clauses 1-16, wherein the semiconductor structures are progressively doped or mixed into one another to create a smooth transition between the semiconductor structures.Attorney Docket No. cap-oi6pct

[0184] 18. The radiation-sensitive device of any of clauses 1-17, further comprising nanostructures of a first material in a matrix of at least one of the semiconductor materials to create localized charge-amplification sites.

[0185] 19. The radiation-sensitive device of any of clauses 1-18, wherein the semiconductor structures are heterostructures or superlattices of alternating layers of different semiconductor materials that generate a band structure for enhanced charged generation and transport.

[0186] 20. The radiation-sensitive device of any of clauses 1-19, wherein the semiconductor structures are inorganic, and wherein the composite semiconductor structure further comprises organic semiconducting charge-transport layers between the inorganic semiconductor structures to improve charge-collection efficiency.

[0187] 21. The radiation-sensitive device of any of clauses 1-20, wherein the composite semiconductor structure comprises at least one charge-transport layer comprising a material having tunable bandgap properties to optimize charge-carrier mobility and reduce recombinant losses.

[0188] 22. The radiation-sensitive device of any of clauses 1-21, wherein the semiconductor structures are configured to form a photodetector array for imaging.

[0189] 23. A method of enhancing radiation detection performance in a radiation-sensitive device, the method comprising:

[0190] providing the radiation-sensitive device of any of clauses 1-22;

[0191] exposing the radiation-sensitive device to incident radiation;

[0192] applying an electric field to the composite semiconductor structure via the plurality of electrodes; and

[0193] generating an intrinsic charge-amplification effect within the composite semiconductor structure, wherein said generating comprises causing charge carriers created by the incident radiation in at least one of the semiconductor structures to induce the generation of additional charge carriers within the composite semiconductor structure, thereby enhancing a signal-to-noise ratio of the radiation-sensitive device.

[0194] 24. The method of clause 23, wherein the electrodes include source and drain electrodes in a field-effect transistor (FET) architecture, and wherein generating the intrinsic charge-amplification effect comprises modulating a current between the source and drain electrodes in response to the charge carriers created by the incident radiation.

[0195] 25. The method of clause 23 or 24, wherein generating the intrinsic chargeamplification effect comprises initiating impact ionization events within a superlattice structure formed by the semiconductor structures.Attorney Docket No. cap-oi6pct

[0196] 26. The method of clause 23 or 24, wherein generating the intrinsic chargeamplification effect comprises trapping and recycling secondary photons using integrated optical structures to stimulate further charge generation.

[0197] 27. The method of clause 23 or 24, wherein generating the intrinsic chargeamplification effect comprises creating multiple electron-hole pairs from a single incident photon via multiple exciton generation (MEG) in quantum dots.

[0198] 28. The method of any of clauses 23-27, wherein the composite semiconductor structure comprises amorphous selenium (a-Se) and cesium lead bromide perovskite (CsPbBr3) layers.

[0199] 29. The method of any of clauses 23-28, wherein the radiation-sensitive device is an X- ray or neutron flat panel radiation detector device.

[0200] 30. The method of any of clauses 23-29, wherein the composite semiconductor structure incorporates a scintillator material, and wherein the scintillator material is selected from cesium iodide (CsI), sodium iodide (Nal), bismuth germanate (BGO), lutetium oxyorthosilicate (LSO), and orgadolinium oxyorthosilicate (GSO).

[0201] 31. The method of any of clauses 23-30, wherein the incident radiation comprises at least one of electromagnetic radiation, particulate radiation, or cosmic rays.

[0202] While this invention has been shown and described with references to particular implementations thereof, those skilled in the art will understand that various substitutions and alterations in form and details may be made therein without departing from the scope of the invention. Further, other aspects, functions, and advantages are also within the scope of the invention, and all implementations of the invention need not necessarily achieve all of the advantages or possess all of the characteristics described above. Additionally, steps, elements, and features discussed herein in connection with one implementation can likewise be used in conjunction with other implementations. The contents of references, including reference texts, journal articles, patents, patent applications, etc., cited throughout the text are hereby incorporated by reference in their entirety for all purposes; and all appropriate combinations of implementations, features, characterizations, and methods from these references and the present disclosure may be included in implementations of this invention. Further still, the components and steps identified in the Background section are integral to this disclosure and can be used in conjunction with or substituted for components and steps described elsewhere in the disclosure within the scope of the invention.

Claims

Attorney Docket No. cap-oi6pctCLAIMSWhat is claimed is:

1. A radiation-sensitive device, comprising:a composite semiconductor structure comprising:a plurality of semiconductor structures, wherein different semiconductor structures comprise different semiconductor materials, wherein the semiconductor structures are architecturally and functionally integrated such that charge carriers generated by incident radiation in one or more of the semiconductor structures cause generation of additional charge carriers within the composite semiconductor structure, thereby producing an intrinsic charge-amplification effect that enhances a signal- to-noise ratio of the radiation-sensitive device; anda plurality of electrodes configured to apply an electric field across the composite semiconductor structure.

2. The radiation-sensitive device of claim 1, wherein the composite semiconductor structure is integrated into a field-effect transistor (FET) architecture, wherein at least one of the semiconductor structures forms a radiation-sensitive channel, and wherein the electrodes comprise interdigitated source and drain electrodes, such that radiation-generated charge carriers in the radiation-sensitive channel modulate a current between the source and drain electrodes to produce the intrinsic charge-amplification effect.

3. The radiation-sensitive device of claim 1, wherein the semiconductor structures form a superlattice of alternating layers, and wherein quantum confinement effects within the superlattice are engineered to enhance impact ionization, contributing to the intrinsic charge-amplification effect.

4. The radiation-sensitive device of claim 1, further comprising optical structures integrated with the composite semiconductor structure, wherein the optical structures are configured to trap and recycle secondary photons generated within the device, thereby stimulating further charge generation to produce the intrinsic charge-amplification effect.

5. The radiation-sensitive device of claim 1, wherein at least one of the semiconductor structures comprises quantum dots capable of multiple exciton generation (MEG), such that a single high-energy incident photon generates multiple electron-hole pairs, producing the intrinsic charge-amplification effect.Attorney Docket No. cap-oi6pct6. The radiation-sensitive device of claim 1, wherein the semiconductor structures are in the form of distinct layers of different semiconductor materials.

7. The radiation-sensitive device of claim 1, wherein the semiconductor materials comprise a plurality of the following semiconductor materials:(a) elemental semiconductors selected from silicon (Si), germanium (Ge), diamond or graphene (C), a-tin (a-Sn), or black phosphorous (P);(b) compound semiconductors selected from:(i) III-V compounds selected from gallium arsenide (GaAs), indium antimonide (InSb), gallium nitride (GaN), aluminum nitride (A1N), boron nitride (BN), aluminum gallium arsenide (AlGaAs), indium gallium arsenide (InGaAs), gallium phosphide (GaP), or indium arsenide (InAs);(ii) II-VI compounds selected from cadmium telluride (CdTe), zinc selenide (ZnSe), zinc sulfide (ZnS), mercury cadmium telluride (HgCdTe), or zinc cadmium telluride (ZnCdTe); or(iii) IV-IV compounds selected from silicon carbide (SiC) or silicon germanium (SiGe);(c) oxide semiconductors selected from zinc oxide (ZnO), titanium dioxide (Ti02), copper oxide (CuO, Cu2O), tin oxide (Sn02), indium tin oxide (ITO), gallium oxide (Ga2O3), or indium gallium zinc oxide (IGZO); (d) organic semiconductors selected from pentacene, rubrene, poly(3- hexylthiophene) (P3HT), phenyl-Cei-butyric acid methyl ester (PCBM), or poly(p-phenylene vinylene) (PPV);(e) perovskite semiconductors selected from methylammonium lead iodide (CH3NH3Pbl3), formamidinium lead iodide (HC(NH2)2PbI3), cesium lead bromide (CsPbBr3), or mixed halide perovskites;(f) chalcogenide semiconductors selected from amorphous selenium (a-Se), lead(II) sulfide (PbS), cadmium sulfide (CdS), copper indium gallium selenide (CIGS), or copper zinc tin sulfide (CZTS), molybdenum disulfide (MoS2), or tungsten diselenide (WSe2);(g) organic-inorganic hybrid semiconductors selected from methylammonium lead iodide (CH3NH3PbI3), or phenethylammonium lead iodide (PEA2PbI4);(h) ceramic semiconductors selected from barium titanate (BaTiO3), strontium titanate (SrTiO3), or lead zirconate titanate (PZT); or(i) ternary semiconductor aluminum gallium indium phosphide (AlGalnP).Attorney Docket No. cap-oi6pct8. The radiation-sensitive device of claim 7, wherein the semiconductor materials comprise at least one of graphene (C), molybdenum disulfide (M0S2), tungsten diselenide (WSe2), hexagonal boron nitride (h-BN), or black phosphorus in a 2D semiconductor layer.

9. The radiation-sensitive device of claim 7, wherein the semiconductor materials comprise at least one of the following in the form of quantum dots: lead(II) sulfide (PbS), cadmium selenide (CdSe), indium arsenide (InAs), or graphene (C).

10. The radiation-sensitive device of claim 7, wherein the semiconductor materials comprise at least one of the following in amorphous form: amorphous silicon (a- Si), amorphous indium gallium zinc oxide (a-IGZO), or amorphous selenium (a- Se); ternary and quaternary compound semiconductors selected from copper indium gallium selenide (CIGS), copper zinc tin sulfide (CZTS), or aluminum gallium indium phosphide (AlGalnP).

11. The radiation-sensitive device of claim 7, wherein the multi-layered semiconductor structure comprises amorphous selenium (a-Se) and cesium lead bromide perovskite (CsPbBr3) layers.

12. The radiation-sensitive device of claim 1, wherein the device is an X-ray flatpanel radiation detector device.

13. The radiation-sensitive device of claim 1, further comprising a scintillator material incorporated into the composite semiconductor structure.

14. The radiation-sensitive device of claim 13, wherein the scintillator material is selected from the following compositions: cesium iodide (CsI), sodium iodide (Nal), bismuth germanate (BGO), lutetium oxyorthosilicate (LSO), gadolinium oxyorthosilicate (GSO), or a combination thereof.

15. The radiation-sensitive device of claim 13, wherein the scintillator material is in the form of a layer disposed on top of or between the semiconductor structures.

16. The radiation-sensitive device of claim 13, wherein the scintillator material is embedded within one or more of the semiconductor structures.Attorney Docket No. cap-oi6pct17. The radiation-sensitive device of claim 1, wherein the semiconductor structures are progressively doped or mixed into one another to create a smooth transition between the semiconductor structures.

18. The radiation-sensitive device of claim 1, further comprising nanostructures of a first material in a matrix of at least one of the semiconductor materials to create localized charge-amplification sites.

19. The radiation-sensitive device of claim 1, wherein the semiconductor structures are hetero structures or superlattices of alternating layers of different semiconductor materials that generate a band structure for enhanced charged generation and transport.

20. The radiation-sensitive device of claim 1, wherein the semiconductor structures are inorganic, and wherein the composite semiconductor structure further comprises organic semiconducting charge-transport layers between the inorganic semiconductor structures to improve charge-collection efficiency.

21. The radiation-sensitive device of claim 1, wherein the composite semiconductor structure comprises at least one charge-transport layer comprising a material having tunable bandgap properties to optimize charge-carrier mobility and reduce recombinant losses.

22. The radiation-sensitive device of claim 1, wherein the semiconductor structures are configured to form a photodetector array for imaging.

23. A method of enhancing radiation detection performance in a radiation-sensitive device, the method comprising:providing the radiation-sensitive device of claim 1;exposing the radiation-sensitive device to incident radiation; applying an electric field to the composite semiconductor structure via the plurality of electrodes; andgenerating an intrinsic charge-amplification effect within the composite semiconductor structure, wherein said generating comprises causing charge carriers created by the incident radiation in at least one of the semiconductor structures to induce the generation of additional charge carriers within the composite semiconductor structure, thereby enhancing a signal-to-noise ratio of the radiation-sensitive device.Attorney Docket No. cap-oi6pct24. The method of claim 23, wherein the electrodes include source and drain electrodes in a field-effect transistor (FET) architecture, and wherein generating the intrinsic charge-amplification effect comprises modulating a current between the source and drain electrodes in response to the charge carriers created by the incident radiation.

25. The method of claim 23, wherein generating the intrinsic charge-amplification effect comprises initiating impact ionization events within a superlattice structure formed by the semiconductor structures.

26. The method of claim 23, wherein generating the intrinsic charge-amplification effect comprises trapping and recycling secondary photons using integrated optical structures to stimulate further charge generation.

27. The method of claim 23, wherein generating the intrinsic charge-amplification effect comprises creating multiple electron-hole pairs from a single incident photon via multiple exciton generation (MEG) in quantum dots.

28. The method of claim 23, wherein the composite semiconductor structure comprises amorphous selenium (a-Se) and cesium lead bromide perovskite (CsPbBr3) layers.

29. The method of claim 23, wherein the radiation-sensitive device is an X-ray or neutron flat panel radiation detector device.

30. The method of claim 23, wherein the composite semiconductor structure incorporates a scintillator material, and wherein the scintillator material is selected from cesium iodide (CsI), sodium iodide (Nal), bismuth germanate (BGO), lutetium oxyorthosilicate (LSO), and orgadolinium oxyortho silicate (GSO).

31. The method of claim 23, wherein the incident radiation comprises at least one of electromagnetic radiation, particulate radiation, or cosmic rays.

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