A light-controlled tunneling response detector, applications and preparation method thereof

Abstract

The application discloses a light-controlled tunneling response detector, a preparation method and application thereof, and comprises a Si / SiO2 substrate, a metal electrode, a WS2 layer, a graphene interlayer and a SnSe2 layer, the tunneling photoelectric detector is integrated with the metal electrode on the Si / SiO2 substrate, and a vertical heterojunction conductive channel composed of WS2 / graphene / SnSe2 is constructed in the area between the metal electrodes; wherein the graphene serves as an intermediate interlayer, is combined with the upper SnSe2 and the lower WS2 through van der Waals force, and forms a vertical stacking structure which is staggered and overlapped with each other. The application realizes dynamic switching of a type II to type III heterojunction, forms an interband quantum tunneling channel, and improves a tunneling probability.

Description

Technical Field

[0001] This invention belongs to the field of photoelectric detection technology, specifically relating to a detector with optically controlled tunneling response, its application, and its preparation method. Background Technology

[0002] In quantum mechanics, quantum tunneling refers to the quantum behavior of microscopic particles like electrons, which can penetrate or traverse potential barriers, even though the height of the barrier is greater than the particle's total energy. Tunneling is one of the most prominent features of quantum mechanics, breaking the limitations of classical physics and having wide and important applications in modern electronics and materials science. Compared to traditional thermionic emission or diffusion mechanisms, tunneling has the following advantages: high response speed, low power consumption, and noise suppression. Controllable tunneling refers to a physical phenomenon in which the electron tunneling process can be actively controlled through external manipulation methods (such as electric fields, optical fields, or stress).

[0003] Transition metal dichalcogenides and selenides are ideal materials for constructing high-performance photodetectors due to their tunable band gaps (1.1-2.1 eV) and excellent carrier mobility. However, single two-dimensional materials have limitations in terms of detection range, response speed, and noise suppression. Therefore, forming van der Waals heterojunctions by vertically stacking different two-dimensional materials has become an important way to overcome performance bottlenecks. Vertical heterojunctions have advantages such as strong compatibility, tunable band structure, and excellent electronic and optical properties. In vertical heterojunctions, efficient carrier transport can be achieved by controlling the barrier height and width through band engineering. The conduction band of WS2 and the valence band of SnSe2 are similar, forming a non-overlapping band structure, which promotes interband tunneling. SnSe2 is a naturally high electron-concentration material—requiring no additional gate voltage control—and forms a built-in electric field with WS2, enhancing tunneling efficiency. As a zero-bandgap half-metal material, graphene can play multiple roles in vertical heterostructures: a carrier transport channel, where graphene's high carrier mobility and ultrathin properties—a single atomic layer—can effectively reduce the width of the tunneling barrier and increase the tunneling probability; and a bandgap modulation medium, where the Fermi level of graphene can be adjusted by gate voltage or chemical doping, which can dynamically optimize the bandgap alignment of the heterostructure, enabling broadband detection—from visible light to infrared—and optimizing the controllability of the tunneling effect.

[0004] In recent years, two-dimensional materials have shown great potential in the field of novel optoelectronic devices due to their unique electronic structure and physical properties. Based on the development of two-dimensional material heterojunctions, tunneling photodetectors have been further developed. Their core principle is to achieve efficient separation and transport of photogenerated carriers through the quantum tunneling effect. Traditional photodetectors—such as PN junctions and Schottky junctions—rely on the drift and diffusion of photogenerated carriers under a built-in electric field, but their response speed and sensitivity are limited by interface recombination and material defects. Two-dimensional materials—such as graphene and transition metal chalcogenides—provide an ideal platform for designing high-performance tunneling devices due to their atomic-level thickness, tunable band structure, and van der Waals interfaces without dangling bonds. The performance of tunneling photodetectors depends on the following key mechanisms: 1. Direct tunneling: Under low bias voltage, the probability of carriers passing through the thin barrier is high, and the current increases linearly with the voltage, I... DT ∝Vexp( ); 2. Fowler-Nordheim tunneling: Under high bias, the barrier is triangular, the tunneling probability increases exponentially, and the current is proportional to the square of the voltage, I FNT ∝Vexp( 3. Interband tunneling: In type III heterojunctions, electrons tunnel directly from the valence band of WS2 material to the conduction band of SnSe2 material, significantly reducing dark current and improving photoresponse speed.

[0005] While existing tunneling photodetectors based on two-dimensional material heterojunctions have shown significant advantages, the following key issues still need to be addressed: the tunneling efficiency of heterojunctions is highly dependent on the band alignment of the material, such as the single band structure of the type III band structure of WS2 / SnSe2. However, the range of selectable band gaps and band positions for existing two-dimensional materials is limited, making it difficult to achieve broadband and efficient tunneling; barrier fluctuations introduced by interface states: although there are no dangling bonds at the van der Waals heterojunction interface, interlayer lattice mismatch leads to uneven local barrier height, causing spatial fluctuations in the tunneling current and increasing noise.

[0006] Therefore, how to solve the problems of inherent bandgap limitation and interface noise, and provide a detector with high responsivity, low noise, and wide spectrum optical tunneling response, its application and preparation method are technical problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0007] The first objective of this invention is to provide a detector with optically controlled tunneling response, addressing the problems in the prior art.

[0008] Therefore, the above-mentioned objectives of the present invention are achieved through the following technical solutions:

[0009] A photodetector with optically controlled tunneling response includes a Si / SiO2 substrate, metal electrodes, a WS2 layer, a graphene intercalation layer, and a SnSe2 layer. The tunneling photodetector integrates metal electrodes on the Si / SiO2 substrate. In the region between the metal electrodes, a vertical heterojunction conductive channel composed of WS2 / graphene / SnSe2 is constructed. The graphene serves as an intermediate intercalation layer and is bonded to the upper SnSe2 layer and the lower WS2 layer through van der Waals forces to form a vertically stacked structure with staggered overlaps.

[0010] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0011] As a preferred embodiment of the present invention: the length of the WS2 layer and the SnSe2 layer are both 25~40μm, the width is 2~6μm, and the thickness is 10~200nm; the length of the graphene intercalation layer is 15~20μm, the width is 6~8μm, and the thickness is 50~300nm.

[0012] As a preferred embodiment of the present invention, the thickness of the Si / SiO2 substrate is 0.5~1mm.

[0013] As a preferred technical solution of the present invention: the metal electrode and the lead wire-shaped metal contact electrode are chromium / gold bar-shaped metal contact electrodes with a thickness of 90~110nm, wherein the thickness of Cr is 5~15nm and the thickness of Au is 85~95nm.

[0014] The second objective of this invention is to provide an application of a detector with optically controlled tunneling response, addressing the problems in the prior art.

[0015] Therefore, the above-mentioned objectives of the present invention are achieved through the following technical solutions:

[0016] The application of optically controlled tunneling response detectors allows for the dynamic switching of the device's band structure between type II and type III under bias voltage conditions, thereby achieving the tunneling effect.

[0017] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0018] As a preferred technical solution of the present invention: under visible to infrared light radiation, the tunneling probability increases, and the tunneling characteristics of the device are further modulated, thereby realizing the excellent multi-band response performance of the device.

[0019] The third objective of this invention is to provide a method for fabricating a detector with optically controlled tunneling response, addressing the problems in the prior art.

[0020] Therefore, the above-mentioned objectives of the present invention are achieved through the following technical solutions:

[0021] The fabrication method of the optically controlled tunneling response detector includes the following steps:

[0022] S1. First, the Si / SiO2 substrate is cleaned and then cut into 1.5 cm × 1.5 cm samples using a cutting technique.

[0023] S2, Ultraviolet lithography alignment marks and electron beam lithography alignment marks are prepared using ultraviolet lithography, electron beam evaporation and lift-off process;

[0024] S3, using PDMS transfer technology, the mechanically exfoliated WS2 layer, graphene intercalation layer, and SnSe2 layer are transferred onto the cleaned Si / SiO2 substrate to achieve good contact between materials;

[0025] S4, strip-shaped metal contact electrodes are prepared using ultraviolet lithography, electron beam evaporation and lift-off process to form good contact;

[0026] S5 uses standard semiconductor packaging technology to package and test devices.

[0027] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0028] As a preferred technical solution of the present invention: the WS2 layer, graphene intercalation layer and SnSe2 layer are sequentially transferred to the metal contact electrode from bottom to top using a mechanical exfoliation dry method.

[0029] Compared with the prior art, the optically controlled tunneling response detector, its application, and its fabrication method of the present invention have the following beneficial effects:

[0030] 1. Achieved broad spectral response and excellent dark current suppression: By constructing a WS2 / SnSe2 heterojunction and inserting graphene as a modulation layer, this structure can form a gap-like bandgap arrangement with a large conduction band shift under zero bias or small bias voltage, thereby fundamentally suppressing the reverse transport of charge carriers and obtaining extremely low reverse dark current. Simultaneously, the device's cutoff wavelength is determined by the heterojunction interface barrier height, rather than the intrinsic bandgap of the non-absorbing layer material. This breaks the dependence on narrow bandgap materials and significantly broadens the detector's operating wavelength range.

[0031] 2. Achieved efficient light-assisted tunneling and fast response: Under illumination, photogenerated carriers generated in WS2 and SnSe2 are efficiently separated within the graphene layer. The synergistic effect of the interface's built-in electric field and the external bias electric field triangulates the potential barrier shape, triggering the (FN) tunneling effect. This "light-assisted tunneling" mechanism significantly improves the tunneling probability and collection efficiency of photogenerated carriers, thereby simultaneously achieving high responsivity and high response speed, overcoming the challenges of low carrier separation efficiency and slow tunneling efficiency in traditional devices.

[0032] 3. Achieved dynamically reconfigurable multi-mode detection capability: This invention, by jointly applying a bias voltage and an optical field and utilizing the sensitive modulation effect of the graphene layer on the energy band, can precisely and dynamically control the band alignment relationship between WS2 and SnSe2. This enables the device to intelligently switch between a broadband detection state dominated by carrier separation and a high-sensitivity, high-speed detection state dominated by tunneling transport. This proactive, programmable band engineering capability is the fundamental reason for obtaining superior performance such as broadband, low dark current, high sensitivity, and high speed, achieving a high degree of integration of multiple functions in a single device.

[0033] Specifically:

[0034] First, wide-spectrum detection and low dark current: In "off" or low-bias mode, the system stabilizes in a Type II / gap-aligned state with a large conduction band offset, effectively suppressing dark current under zero or low bias in principle, laying the foundation for high-performance detection at room temperature. Simultaneously, the detector's cutoff wavelength is determined by the heterojunction barrier height, eliminating dependence on a single material's narrow bandgap and thus achieving a "widening" of the operating wavelength range.

[0035] Second, high responsivity and high sensitivity: In detection mode, photogenerated carriers are efficiently separated in the graphene layer by applying a reverse bias and introducing illumination. The superposition of the built-in electric field and the external electric field at the interface triangulates the potential barrier, triggering (FN) tunneling. This "light-assisted tunneling" mechanism significantly improves the tunneling probability and collection efficiency of photogenerated carriers, directly resulting in an order-of-magnitude increase in responsivity and sensitivity.

[0036] Third, high-speed response: The high mobility of graphene ensures ultrafast transport of charge carriers, while the introduction of photoelectric field can instantaneously modulate the shape of the barrier, accelerating the tunneling process itself, thus achieving a speed far exceeding that of traditional photovoltaic or photoconductor modes. Attached Figure Description

[0037] Figure 1 This is a cross-sectional view of the tunneling photodetector of the present invention;

[0038] Figure 2 This is a plan view of the tunneling photodetector of the present invention;

[0039] Figure 3 This is a fitting curve of ln(current / voltage²) and 1 / voltage for the tunneling photodetector of the present invention when the bias voltage is less than 0 in the absence of light.

[0040] Figure 4 The transfer characteristic current-voltage fitting interband tunneling curve at 0; the tunneling photodetector of this invention, under no-light conditions, when the bias voltage is large

[0041] like Figure 5 The tunneling photodetector of the present invention, under 638nm laser radiation, shows two tunneling fitting curves for ln(current / voltage²) and 1 / voltage when the bias voltage is greater than 0.

[0042] like Figure 6 This is a fitting curve of ln(current / voltage 2) and ln(1 / voltage) for the tunneling photodetector of the present invention under 638nm laser radiation when the bias voltage is less than 0.

[0043] like Figure 7 The optical response diagrams of the tunneling photodetector of the present invention to laser wavelengths of 520nm, 638nm, 940nm and 1550nm under a bias voltage of 2V are shown.

[0044] like Figure 8 The photocurrent diagrams of the tunneling photodetector of the present invention, under 638nm laser radiation and bias voltage of 2V, show the photocurrent dependence of different incident power at 0V, 1V and 2V.

[0045] like Figure 9 This is a graph showing the optical response speed of the tunneling photodetector of the present invention under a bias voltage of 2V under 638nm laser radiation. Detailed Implementation

[0046] The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

[0047] The detector with optically controlled tunneling response of the present invention

[0048] The purpose of this invention is to propose a method for fabricating a photodetector exhibiting a tunneling effect. This method employs a mechanical exfoliation method to transfer mechanically exfoliated WS2 (4), graphene (5), and SnSe2 (6) onto a metal contact electrode (3) / SiO2 (2) / Si (1) substrate to fabricate a vertical heterojunction tunneling detector. This method features a simple fabrication process, low cost, ease of vertical integration, and the ability to achieve the tunneling effect.

[0049] The objective of this invention is achieved through the following technical solution:

[0050] A detector with optically controlled tunneling response includes a WS2 layer 4, a graphene intercalation layer 5, a SnSe2 layer 6, and a metal contact electrode 3; the WS2 layer 4, graphene intercalation layer 5, and SnSe2 layer 6 are arranged in order from bottom to top.

[0051] The WS2 layer (4), graphene intercalation layer (5) and SnSe2 layer (6) were sequentially transferred to the insulating layer from bottom to top using a dry mechanical peeling method.

[0052] The thickness of the WS2 layer (4) ranges from 10 nm to 200 nm, the thickness of the graphene intercalation layer (5) ranges from 50 nm to 300 nm, and the thickness of the SnSe2 layer (6) ranges from 10 nm to 200 nm.

[0053] The metal contact electrode (3) is a Cr / Au electrode, where Cr is the adhesive layer that contacts the insulating layer and Au is the metal conductive layer.

[0054] Its total thickness is 90~110 nm, the thickness of Cr is 5 nm~15 nm, and the thickness of Au is 85 nm~95 nm.

[0055] The beneficial effects of this invention are as follows: 1. High-performance tunneling rectification and low dark current: WS2 and SnSe2 form a type II heterojunction, and graphene is inserted between WS2 and SnSe2. Graphene acts as a high-mobility carrier transport channel, constructing a gap band alignment and forming a large conduction band shift under zero bias, effectively suppressing reverse dark current. Under reverse bias, the high carrier concentration of graphene and the narrow bandgap characteristics of SnSe2 synergistically optimize the tunneling probability, significantly enhancing the reverse tunneling current. Simultaneously, it avoids the interface recombination loss of traditional heterojunctions. Furthermore, the use of graphene as an intercalation layer provides a gapless characteristic, expanding the spectral width. 2. At room temperature and in the absence of light, electrons in the material still gain thermal energy, and some high-energy electrons can cross or tunnel through the potential barrier. Furthermore, thanks to the metallic transport properties of graphene... 1. Graphene's zero-bandgap characteristic as an intercalation layer makes its Fermi level susceptible to charge transfer between the two materials, forming a localized built-in electric field. This electric field can reduce the effective barrier thickness and increase the tunneling probability. 2. Under illumination control, photogenerated electron-hole pairs of WS2 and SnSe2 achieve efficient separation through the graphene layer and form photo-assisted tunneling driven by the interface electric field, enhancing the tunneling probability (the photogenerated electric field and the applied electric field superimpose, the barrier triangulates, triggering FN tunneling, further regulating the device's tunneling characteristics). 3. Dynamic bandgap modulation and multi-mode switching: By modulating the bias voltage and optical field, as well as optimizing the bandgap of graphene, the bands of WS2 and SnSe2 are adjusted, enabling dynamic switching from type II to type III heterojunctions, forming an interband quantum tunneling channel, and increasing the tunneling probability.

[0056] Example 1

[0057] This invention discloses a high-response, broadband graphene intercalation tunneling photodetector, such as... Figure 1 As shown, it includes 1. silicon, 2. insulating silicon dioxide, 3. strip-shaped metal contact electrode, 4. WS2 layer, 5. graphene intercalation layer, and 6. SnSe2 layer.

[0058] First, the silicon / insulating silicon dioxide substrate is cleaned, and then cut into 1.5cm × 1.5cm samples using a cutting technique.

[0059] Alignment marks made by ultraviolet lithography (AZ5214 photoresist), electron beam evaporation, and lift-off were prepared using ultraviolet lithography and electron beam lithography (Cr / Au).

[0060] By using transfer technology with PDMS to transfer WS2, graphene, and SnSe2 from the substrate to a cleaned silicon / insulating silicon dioxide substrate with alignment marks, the detector's response in various wavelength bands can be achieved.

[0061] Metal strip-shaped metal contact electrodes (Cr / Au) were fabricated using ultraviolet lithography, electron beam evaporation, and lift-off processes to form good ohmic contacts.

[0062] In the chromium-gold double-layer strip metal contact electrode 3, the thickness of chromium is 5nm to 100nm, and the thickness of Au is 5nm to 100nm.

[0063] WS2 layer 4 is a wide-bandgap two-dimensional material made of WS2 with a thickness ranging from 10 nm to 200 nm; SnSe2 layer 6 is a narrow-bandgap two-dimensional material made of SnSe2 with a thickness ranging from 10 nm to 200 nm, and the intercalation layer is graphene with a thickness ranging from 50 nm to 300 nm.

[0064] The WS2 layer 4, graphene intercalation layer 5, and SnSe26 layer were sequentially transferred from bottom to top onto the strip-shaped metal contact electrode using a dry mechanical exfoliation method.

[0065] Preferably, the WS2 layer 4 of WS2 is transferred using a transfer platform, with a thickness ranging from 10 nm to 200 nm; then the graphene intercalation layer 5 is transferred using a transfer platform, with a thickness ranging from 50 nm to 300 nm; finally, the SnSe2 layer 6 of SnSe2 is transferred using a transfer platform, with a thickness ranging from 10 nm to 200 nm.

[0066] The photodetector of this invention was finally manufactured.

[0067] like Figure 1 The image shown is a cross-sectional view of the tunneling photodetector of the present invention.

[0068] like Figure 2The image shown is a plan view of the tunneling photodetector of the present invention.

[0069] like Figure 3 As shown, this is the ln(current / voltage) of the tunneling photodetector of the present invention when the bias voltage is less than 0 in the absence of light. 2 The fitting curves of the two tunneling modes, 1 / voltage and 1, show that in the dark state, the energy band of the optically controlled tunneling response detector of the present invention is arranged in a "segmental gap" pattern, and the carrier transport is dominated by tunneling. The barrier height is relatively large, which effectively suppresses the reverse dark current and verifies the low noise characteristics of the optically controlled tunneling response detector of the present invention under zero bias / small bias voltage.

[0070] like Figure 4 The figure shows the current-voltage fitting interband tunneling curve of the tunneling photodetector of the present invention under the condition of no light when the bias voltage is greater than 0. It shows that the band alignment is dynamically adjusted under the forward bias voltage, which confirms the flexible control capability of graphene intercalation on the band structure and provides a basis for multi-mode detection.

[0071] like Figure 5 As shown, this is the tunneling photodetector of the present invention under 638nm laser radiation, when the bias voltage is greater than 0, ln(current / voltage) 2 The fitting curves of the two tunneling methods, 1 / voltage and 1, show that illumination significantly enhances the tunneling probability. After efficient separation in the graphene layer, photogenerated carriers tunnel rapidly through the triangular barrier, thereby greatly improving the responsivity.

[0072] like Figure 6 As shown, this is the ln(current / voltage) of the tunneling photodetector of the present invention under 638nm laser radiation when the bias voltage is less than 0. 2 The fitting curve of direct tunneling with 1 / voltage shows that under the combined effect of reverse bias and illumination, the tunneling mechanism can be flexibly switched with the bias polarity, further highlighting the intelligence of the device's coordinated control of optical and electric fields.

[0073] like Figure 7 The figure shows the photocurrent diagram of the tunneling photodetector of the present invention for the light response of laser wavelengths of 520nm, 638nm, 940nm and 1550nm under a bias voltage of 2V. The photocurrent diagram shows the photocurrent response of the optically controlled tunneling response detector of the present invention to have a wide spectrum response capability in the visible to near-infrared band, and the responsivity remains stable at different wavelengths, breaking through the dependence of traditional detectors on narrow bandgap materials.

[0074] like Figure 8The figure shows the photocurrent dependence of the tunneling photodetector of the present invention under different incident power at bias voltages of 0V, 1V and 2V when the bias voltage is 2V under 638nm laser radiation. It shows that efficient photoelectric conversion can be achieved in the range from zero bias to low bias voltage, and it still has a considerable response under zero bias voltage, which further verifies its low power consumption and high sensitivity characteristics.

[0075] like Figure 9 When the bias voltage of the tunneling photodetector of the present invention is 2V under 638nm laser radiation, the rise / fall time of the detector of the present invention with optical control tunneling response is on the order of microseconds, which is significantly faster than that of traditional photovoltaic or photoconductive detectors.

[0076] This invention achieves dynamic reconstruction of the band structure and optically assisted tunneling effect through the synergistic design of WS2 / SnSe2 heterojunction and graphene modulation layer, enabling a single device to simultaneously possess multifunctional integration capabilities such as wide-spectrum response, extremely low dark current, high responsivity, high sensitivity and high-speed response.

[0077] This invention effectively optimizes the interface bandgap arrangement by leveraging the unique electronic structure of graphene, and dynamically switches the device's bandgap structure between type II and type III by applying an external electric field, enabling the device to exhibit various tunneling characteristics. Under visible to infrared light irradiation, the tunneling probability increases, further modulating the device's tunneling characteristics to achieve excellent multi-band response performance. The advantages of this invention are: fast device response speed, wide response band, high responsivity, simple fabrication process, and good repeatability. This invention proposes a strategy for realizing multi-band photodetectors based on controllable tunneling effects.

[0078] In the optically controlled tunneling response detector of this invention, high-performance tunneling rectification and low dark current are achieved. WS2 and SnSe2 form a type II heterojunction, with graphene inserted between WS2 and SnSe2. Graphene serves as a high-mobility carrier transport channel, creating a gap band alignment and forming a large conduction band shift under zero bias, effectively suppressing reverse dark current. Under reverse bias, the high carrier concentration of graphene and the narrow bandgap characteristics of SnSe2 synergistically optimize the tunneling probability, significantly enhancing the reverse tunneling current while avoiding the problems associated with traditional heterojunctions. The system addresses several key aspects: 1) Interface recombination losses, achieving high-performance tunneling rectification and low dark current. Furthermore, the use of graphene as an intercalation layer provides a gapless bandgap, expanding the spectral width, significantly reducing reverse dark current, improving reverse tunneling efficiency, avoiding interface recombination losses, and simultaneously extending the spectral response width. 2) Tunneling optimization under room temperature and no-light conditions: Utilizing the metallic transport channels and zero-bandgap properties of graphene, a localized built-in electric field is formed through charge transfer, reducing the effective barrier thickness and promoting hot electron tunneling. This solves the problem of limited dark current caused by the difficulty of hot electrons crossing or tunneling through the barrier at room temperature. The problem is that by reducing the barrier thickness through an internal electric field, the probability of hot electron tunneling is increased, thus enhancing the sensitivity of the device under no-light conditions; 3. Light-controlled tunneling enhancement: Under light control, photogenerated electron-hole pairs generated by WS2 and SnSe2 achieve efficient separation through the graphene layer, and form light-assisted tunneling driven by the interface electric field. The interface electric field and the applied electric field are superimposed, causing the barrier triangulation, triggering FN tunneling, and enhancing the tunneling probability. This solves the problem of low photogenerated carrier separation efficiency and tunneling probability limited by the static barrier in traditional photodetectors. The photogenerated electric field and the applied electric field are superimposed, causing the barrier triangulation, triggering FN tunneling, and enhancing the tunneling probability. Field synergy enables optically assisted tunneling, significantly improving tunneling probability and photoresponse speed; 4. Dynamic bandgap modulation and multi-mode switching: By combining bias voltage and optical field modulation with graphene intercalation to optimize the bandgap, the transition of WS2 and SnSe2 heterojunctions from type II to type III is dynamically adjusted, forming an interband quantum tunneling channel. This solves the problem that fixed bandgap structures limit the flexibility of tunneling modes and make it difficult to adapt to the detection needs of multiple scenarios. It enables dynamic switching of heterojunction types, provides multi-mode tunneling channels, and significantly enhances device tunability and application prospects.

[0079] The detector of this invention solves problems such as dark current suppression, tunneling efficiency improvement, spectral expansion and dynamic response through graphene intercalation bandgap engineering and photoelectric synergistic control. It realizes a high-sensitivity, low-power, wide-spectrum and multi-mode switching optically controlled tunneling device, which has great application prospects in the fields of photoelectric detection and quantum device applications in complex environments.

[0080] The above specific embodiments are used to explain and illustrate the present invention, and are only preferred embodiments of the present invention, not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A detector with optically controlled tunneling response, characterized in that: The structure includes a Si / SiO2 substrate, metal electrodes, a WS2 layer, a graphene intercalation layer, and a SnSe2 layer. The metal electrodes are integrated on the Si / SiO2 substrate, and a WS2 / graphene / SnSe2 vertical van der Waals heterojunction conductive channel is constructed between the metal electrodes. The graphene intercalation layer serves as an intermediate intercalation layer and is bonded to the upper SnSe2 layer and the lower WS2 layer through van der Waals forces to form a vertically stacked structure that overlaps with each other.

2. The detector based on optically controlled tunneling response according to claim 1, characterized in that: The length of the WS2 layer and the SnSe2 layer are both 25~40μm, the width is 2~6μm, and the thickness is 10~200nm; the length of the graphene intercalation layer is 15~20μm, the width is 6~8μm, and the thickness is 50~300nm.

3. The detector with optically controlled tunneling response according to claim 1, characterized in that: The thickness of the Si / SiO2 substrate is 0.5~1mm.

4. The detector with optically controlled tunneling response according to claim 1, characterized in that: The metal electrode is a Cr / Au composite electrode with a thickness of 90 nm to 110 nm, wherein the thickness of Cr is 5 to 15 nm and the thickness of Au is 85 to 95 nm.

5. The application of the detector employing the optically controlled tunneling response of any one of claims 1-4, characterized in that: Under bias voltage, the device dynamically switches between type II and type III band structures, thereby achieving the tunneling effect.

6. The application of the detector with optically controlled tunneling response according to claim 5, characterized in that: Under visible to infrared radiation, the tunneling probability increases, and by further modulating the tunneling characteristics of the device, excellent multi-band response performance of the device is achieved.

7. A method for fabricating a detector with optically controlled tunneling response according to any one of claims 1-4, characterized in that: Includes the following steps: S1. First, the Si / SiO2 substrate is cleaned and then cut into 1.5 cm × 1.5 cm samples using a cutting technique. S2, Ultraviolet lithography alignment marks and electron beam lithography alignment marks are prepared using ultraviolet lithography, electron beam evaporation and lift-off process; S3, using PDMS transfer technology, the mechanically exfoliated WS2 layer, graphene intercalation layer, and SnSe2 layer are transferred onto the cleaned Si / SiO2 substrate to achieve good contact between materials; S4, strip-shaped metal contact electrodes are prepared using ultraviolet lithography, electron beam evaporation and lift-off process to form good contact; S5 uses semiconductor packaging technology to package and test devices.

8. The method for fabricating a detector with optically controlled tunneling response as described in claim 7, characterized in that: The WS2 layer, graphene intercalation layer, and SnSe2 layer are sequentially transferred onto the Si / SiO2 substrate from bottom to top using a dry mechanical exfoliation method and make good contact with the metal electrode.

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