A nano-optoelectronic device based on Hf2CO2 MXene and its control method

Abstract

The application belongs to the technical field of photoelectric functional materials, and particularly relates to a nano photoelectric device based on Hf2CO2 MXene and a regulation method thereof. The nano photoelectric device comprises a two-dimensional semiconductor functional layer composed of Hf2CO2 monolayer material, and the carrier transport direction of the two-dimensional semiconductor functional layer is along the zigzag crystal direction of the Hf2CO2 material. The regulation method comprises: applying a biaxial in-plane tensile strain greater than 0 and not more than 8% to the Hf2CO2 monolayer material, and then regulating the electrical transmission characteristics and / or photoelectric response characteristics of the nano photoelectric device. The biaxial in-plane tensile strain regulation method provided by the application does not need to change the chemical composition of Hf2CO2, is different from irreversible modification methods such as doping and compounding, can continuously and reversibly modulate the energy band and photoelectric characteristics of the material, and realizes on-demand regulation of the device performance.

Description

Technical Field

[0001] This invention belongs to the field of optoelectronic functional materials technology, specifically relating to a nano-optoelectronic device based on Hf2CO2 MXene and its control method. Background Technology

[0002] Two-dimensional materials, due to their ultrathin atomic structure and unique optoelectronic, mechanical, and physicochemical properties, have become core candidate material systems for overcoming the size limitations and functional constraints of traditional silicon-based semiconductors. Among various two-dimensional materials, MXenes (transition metal carbides / nitrides) have been widely studied in the microelectronics field due to their advantages such as tunable composition, abundant surface functional groups, and excellent conductivity and mechanical flexibility. However, this material family has significant shortcomings. Most MXenes exhibit intrinsic metallic conductivity, making it difficult to form the depletion layer required for semiconductor devices. This hinders the realization of functions such as gate switching and photodetectors, significantly limiting their practical applications in logic and optoelectronic devices.

[0003] Among the few MXenes possessing semiconductor properties, Hf₂CO₂ is a class predicted by classical theory to have significant application value. Its surface is stably bound with oxygen-containing functional groups, its lattice structure is not prone to failure, and it possesses a suitable intrinsic bandgap to meet the operational requirements of optoelectronic devices. Theoretically, it can be used to fabricate multifunctional nano-optoelectronic devices, possessing considerable industrialization potential. However, current research largely remains at the level of theoretical simulation of physical properties, and has not yet established a complete technological path from materials to practical devices.

[0004] Current research focuses solely on analyzing the inherent static properties of MXenes, lacking comprehensive solutions for dynamically adjusting the performance of Hf₂CO₂ devices, particularly the development and utilization of strain control techniques. In fact, strain engineering can continuously and dynamically alter the electronic band structure, carrier transport characteristics, and light-material interaction mechanisms of materials through controllable lattice deformation. This allows for flexible adjustment of key parameters such as device rectification characteristics, switching current, and spectral response range, enabling customized device functionality. However, this strain control approach has not yet been applied to the Hf₂CO₂ material system, and the development of controllable strain control techniques adapted to this semiconductor MXene is urgently needed in this field. Summary of the Invention

[0005] The first objective of this invention is to provide a method for regulating Hf2CO2 MXene-based nano-optoelectronic devices. This method achieves precise modulation of the material's electronic transport properties, field effects, and photoelectric properties by applying controllable biaxial tensile strain to the two-dimensional semiconductor functional layer in the nano-optoelectronic device, thereby significantly improving or changing the photoelectric performance.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for controlling a nano-optoelectronic device based on Hf2CO2 MXene, the nano-optoelectronic device comprising a two-dimensional semiconductor functional layer composed of a Hf2CO2 monolayer material, wherein the carrier transport direction of the two-dimensional semiconductor functional layer is along the zigzag crystal orientation of the Hf2CO2 material; the control method comprises: applying an in-plane biaxial tensile strain greater than 0 and not exceeding 8% to the Hf2CO2 monolayer material, thereby controlling the electrical transport characteristics and / or photoelectric response characteristics of the nano-optoelectronic device.

[0007] Within this strain range, the band gap of Hf2CO2 can be continuously adjusted, such as... Figure 1 As shown, the band gap of Hf2CO2 increases from about 1.57 eV in the unstrained state to about 1.83 eV when a 4% strain is applied, and further increases to about 1.94 eV when an 8% strain is applied. This "strain engineering" modulation of the band gap provides a basis for controlling the optoelectronic properties of nano-optoelectronic devices.

[0008] Furthermore, the nano-optoelectronic device is a lateral pn junction diode constructed along the serrated crystal orientation of the Hf2CO2 material; by applying in-plane biaxial tensile strain to the Hf2CO2 material, the rectification performance and current driving capability of the pn junction diode are improved.

[0009] Furthermore, by applying an 8% in-plane biaxial tensile strain to the Hf2CO2 monolayer material, the forward current density of the pn junction diode reaches over 47 mA / mm², and the rectification ratio is increased to 10. 7 above.

[0010] Furthermore, the nano-optoelectronic device is a field-effect transistor using Hf2CO2 monolayer material as the pin-type channel layer; by applying the in-plane biaxial tensile strain and simultaneously applying the gate voltage, the carrier injection and transport efficiency in the channel is synergistically controlled, thereby improving the output current density of the field-effect transistor.

[0011] Furthermore, when the gate voltage is -4 V and an in-plane biaxial tensile strain of 8% is applied to the Hf2CO2 monolayer material, the maximum output current density of the field-effect transistor is not less than 1000 mA / mm.

[0012] Furthermore, the nano-optoelectronic device is a photodetector with Hf2CO2 monolayer material as the photoelectric conversion functional layer, and the spectral response characteristics of the photodetector are modulated by applying the in-plane biaxial tensile strain.

[0013] Furthermore, after applying in-plane biaxial tensile strain to the Hf₂CO₂ monolayer material, the intrinsic photocurrent density of the photodetector is 1.2 mA / mm². 2The above results indicate that the light response spectrum undergoes a blue shift.

[0014] Furthermore, the method for applying the in-plane biaxial tensile strain is as follows: transferring or directly growing the Hf2CO2 monolayer material onto a flexible or stretchable substrate with a predetermined coefficient of thermal expansion, mechanically stretching the substrate to transfer strain to the Hf2CO2 monolayer, or generating a difference in the coefficient of thermal expansion between the substrate and the Hf2CO2 monolayer through temperature control, and transferring strain to the Hf2CO2 monolayer by thermal mismatch.

[0015] Furthermore, the aforementioned control method can be implemented alone, or in combination with gate bias control, chemical doping, and heterostructure construction to achieve multi-dimensional synergistic control.

[0016] The second objective of this invention is to provide a nano-optoelectronic device based on Hf2CO2 MXene, which can continuously and reversibly change the optoelectronic properties of the device by adjusting the strain magnitude.

[0017] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A nano-optoelectronic device based on Hf2CO2 MXene includes a two-dimensional semiconductor functional layer composed of a single layer of Hf2CO2 material, wherein the carrier transport direction of the two-dimensional semiconductor functional layer is along the zigzag crystal orientation of the Hf2CO2 material, and the single layer of Hf2CO2 material is subjected to an in-plane biaxial tensile strain of 4% to 8%; the nano-optoelectronic device is one of a pn junction diode, a field-effect transistor, or a photodetector.

[0018] Furthermore, the pn junction diode contains p-type doped regions and n-type doped regions arranged along a sawtooth crystal orientation; the pin junction field-effect transistor includes p + Source region, intrinsic channel, n + The drain region, above and / or below the channel, is provided with a gate insulating layer and a gate metal layer to adapt to the negative gate voltage; the lateral pin phototransistor is arranged with a p-type doped region, an intrinsic light absorption region and an n-type doped region in sequence.

[0019] The beneficial technical effects of this invention are as follows: 1. The in-plane biaxial tensile strain modulation method provided by this invention does not require modification of the chemical composition of Hf₂CO₂. Unlike irreversible modification methods such as doping and composite, it can continuously and reversibly modulate the material's band structure and photoelectric properties, enabling on-demand control of device performance. This method introduces strain through two pathways: mechanical stretching or thermal mismatch. The process is simple and compatible with existing fabrication procedures. The strain range can be controlled to be greater than 0 and not exceeding 8%, without damaging the monolayer material lattice. It is also universally applicable to three types of devices: pn junction diodes, pin field-effect transistors, and pin phototransistors. Furthermore, it can be combined with gate voltage and doping to achieve multi-dimensional synergistic control, significantly expanding the device's adjustable range.

[0020] 2. The Hf2CO2 nano-optoelectronic device disclosed in this invention uses a single-layer material prepared along a zigzag crystal orientation as the functional layer, which provides uniform and stable carrier transport and integrates multiple functions such as rectification, gate-controlled amplification, and photodetection. The device adopts a flexible and stretchable substrate, which can stably transmit uniform biaxial strain and is suitable for flexible electronics applications. Different types of devices have their own unique operating advantages. The field-effect transistor can achieve coordinated control of gate voltage and strain, and the phototransistor can operate with low power consumption under zero bias and zero gate voltage conditions. The entire device can dynamically reconstruct its operating parameters based on the aforementioned control scheme, and can adapt to various operating requirements without changing the structure, effectively reducing the fabrication cost of multifunctional optoelectronic arrays. Attached Figure Description

[0021] Figure 1 The diagram shows the changes in the electronic band structure of Hf2CO2 MXene material under different in-plane biaxial tensile strains. Figure 2 This is a schematic diagram of the single-layer atomic structure of Hf2CO2; Figure 3 (a) is the pn junction diode model based on Hf2CO2 in Embodiment 1 of the present invention. Figure 3 (bd) is a comparison of the current-voltage (IV) characteristic curves of the pn junction diode under different strains; Figure 4 (a) is the Hf2CO2-based field-effect transistor model in Embodiment 2 of the present invention. Figure 4 (bd) is a diagram of the saturated output current density of the field-effect transistor under different strains; Figure 5 (a) is the Hf2CO2-based phototransistor model in Embodiment 3 of the present invention. Figure 5 (bd) is a graph showing the spectral response (photocurrent density - photon energy) of the phototransistor under different strains. Detailed Implementation

[0022] The following is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, all reagents or instruments used are conventional products obtained through commercial channels.

[0023] All data in this invention are derived from simulations, which are performed using quantum transport simulation software (such as QuantumATK) based on density functional theory (DFT) and non-equilibrium Green's function (NEGF) methods.

[0024] Example 1 Example 1 provides a method for controlling a lateral pn junction diode based on Hf2CO2 MXene. This method can achieve real-time adjustment of the photoelectric performance of the lateral pn junction diode by relying on strain. The specific fabrication process is as follows: (1) First, device modeling and construction are performed. Figure 2 Based on the Hf2CO2 monolayer atomic structure shown, a lateral pn junction diode model was constructed along the zigzag crystal orientation (see [reference]). Figure 3 (a)). The functional layer of this device is a single layer of Hf2CO2, with the central region being the intrinsic region. The left and right contact regions are formed into source and drain terminals by p-type and n-type chemical doping, respectively, and metal electrodes are fabricated on both sides to form a lateral diode structure. The substrate is a flexible PDMS stretchable substrate to facilitate the subsequent introduction of in-plane biaxial tensile strain.

[0025] (2) The Hf2CO2 monolayer was transferred onto the PDMS substrate, and the substrate was uniformly stretched in both directions using a stretching table. Biaxial tensile strains of 0%, 4% and 8% were introduced respectively, thereby achieving continuous control of device performance.

[0026] For the constructed Hf₂CO₂ lateral pn junction diode, the current-voltage (IV) characteristic curves under no strain (0%), 4% and 8% biaxial tensile strain were calculated using quantum transport simulation software (such as QuantumATK) based on density functional theory and the non-equilibrium Green's function method. During testing, forward and reverse bias voltages were applied along the sawtooth crystal orientation, and the on-state current density, threshold voltage and reverse saturation current were recorded. The test results are as follows: Figure 3 As shown in (bd), as the strain increases from 0% to 8%, the forward current density reaches over 47 mA / mm², the threshold voltage shifts, the reverse saturation current is effectively suppressed, and the rectification ratio increases by several orders of magnitude, reaching a maximum of 10. 7The above demonstrates the effect of strain on optimizing the rectification performance of diodes.

[0027] Example 2 Example 2 provides a method for controlling the electrical performance of a lateral pin field-effect transistor based on Hf2CO2 MXene. This method can achieve control over electrical performance through strain engineering. The specific fabrication process is as follows: (1) First, complete the device modeling. Fabricate a lateral pin junction field-effect transistor with a top-gate and bottom-gate dual-gate structure (see...). Figure 4 (a) Its channel layer is a single layer of Hf2CO2 along the serrated crystal orientation, which is sequentially divided into p + Source region, intrinsic i-channel region and n + The drain region; gate insulating layers and metal gates are deposited on both sides of the channel to accommodate negative gate voltage control. The entire device is fabricated on a flexible and stretchable substrate to achieve uniform biaxial tensile strain applied to the channel region individually.

[0028] (2) With the gate voltage Vg = -4 V fixed, biaxial tensile strains of 0%, 4% and 8% were applied to the channel region respectively to investigate the effect of strain on the output characteristics of the device.

[0029] For the constructed dual-gate Hf₂CO₂ lateral pin field-effect transistor, under the conditions of a fixed gate voltage Vg = -4V and a drain-source voltage scan range of -1.0-1.0 V, biaxial tensile strains of 0%, 4%, and 8% were applied to the channel region, and its output characteristic curves were tested. The same quantum transport simulation method was used for the tests, and the saturated output current density under different strains was recorded. Figure 4 As shown in (bd), the saturation current density increases significantly with increasing strain, especially at 8% strain, where the peak current density reaches about 1000 mA / mm, which fully verifies the enhancing effect of the synergistic effect of strain and gate voltage on carrier transport efficiency.

[0030] Example 3 Example 3 provides a method for controlling a lateral pin phototransistor based on Hf2CO2 MXene. This device can operate under zero bias conditions, and its photodetector performance can be adjusted by strain. The specific fabrication process is as follows: (1) First, device modeling is performed to build a lateral pin phototransistor operating at zero bias (see Figure 5 (a) The functional absorption layer is a zigzag-oriented Hf2CO2 monolayer, arranged sequentially as p-doped region, intrinsic light absorption region and n-doped region; the device has no external gate and operates in zero-bias and zero-gate voltage low-power mode. The flexible substrate provides support and allows continuous application of 0%-8% biaxial tensile strain to the active region of the device.

[0031] (2) Under zero bias and zero gate voltage conditions, 4% and 8% in-plane biaxial tensile strain were applied to the active region, respectively, and the spectral response characteristics of the phototransistor under different strain conditions were investigated.

[0032] For the zero-bias, zero-gate-voltage Hf₂CO₂ lateral pin phototransistor of Example 3, the intrinsic photocurrent response under monochromatic light illumination was simulated. During testing, the incident photon energy was scanned under biaxial tensile strain conditions of 0%, 4%, and 8%, and the relationship between photocurrent density and photon energy was recorded. The test results are as follows: Figure 5 As shown in (bd), without strain, the response peaks are located at approximately 2.5 eV (blue-green light) and 4.2 eV (ultraviolet light); after applying strain, the main response peak shifts to the blue region in the ultraviolet region, and multiple enhancement peaks are generated at the new energy positions, with the highest peak photocurrent density reaching 1.2 mA / mm². 2 The test results demonstrate that by changing the strain magnitude, the spectral sensitivity range of the phototransistor can be continuously tuned, enabling broadband tunable detection from visible light to ultraviolet light.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. A method for controlling a nano-optoelectronic device based on Hf₂CO₂ MXene, wherein the nano-optoelectronic device comprises a two-dimensional semiconductor functional layer composed of a single layer of Hf₂CO₂ material, characterized in that, The carrier transport direction of the two-dimensional semiconductor functional layer is along the serrated crystal orientation of the Hf2CO2 material; the control method includes: applying an in-plane biaxial tensile strain greater than 0 and not exceeding 8% to the Hf2CO2 monolayer material, thereby controlling the electrical transmission characteristics and / or photoelectric response characteristics of the nano-optoelectronic device.

2. The method for controlling Hf₂CO₂ MXene-based nano-optoelectronic devices according to claim 1, characterized in that, The nano-optoelectronic device is a lateral pn junction diode constructed along the serrated crystal orientation of Hf2CO2 material; by applying in-plane biaxial tensile strain to the Hf2CO2 material, the rectification performance and current driving capability of the pn junction diode are improved.

3. The method for controlling Hf2CO2 MXene-based nano-optoelectronic devices according to claim 2, characterized in that, Applying an 8% in-plane biaxial tensile strain to the Hf2CO2 monolayer material resulted in a forward current density of over 47 mA / mm² for the pn junction diode, increasing the rectification ratio to 10. 7 above.

4. The method for controlling the Hf2CO2 MXene-based nano-optoelectronic device according to claim 1, characterized in that, The nano-optoelectronic device is a field-effect transistor using Hf2CO2 monolayer material as the pin-type channel layer; by applying the in-plane biaxial tensile strain and the gate voltage simultaneously, the carrier injection and transport efficiency in the channel are synergistically controlled, thereby improving the output current density of the field-effect transistor.

5. The method for controlling Hf2CO2 MXene-based nano-optoelectronic devices according to claim 4, characterized in that, When the gate voltage is -4 V and an in-plane biaxial tensile strain of 8% is applied to the Hf2CO2 monolayer material, the maximum output current density of the field-effect transistor is not less than 1000 mA / mm.

6. The method for controlling the Hf2CO2 MXene-based nano-optoelectronic device according to claim 1, characterized in that, The aforementioned nano-optoelectronic device is a photodetector using Hf2CO2 monolayer material as the photoelectric conversion functional layer. The spectral response characteristics of the photodetector are modulated by applying the in-plane biaxial tensile strain.

7. The method for controlling Hf₂CO₂ MXene-based nano-optoelectronic devices according to claim 6, characterized in that, After applying in-plane biaxial tensile strain to the Hf₂CO₂ monolayer material, the intrinsic photocurrent density of the photodetector is 1.2 mA / mm². 2 The above results indicate that the light response spectrum undergoes a blue shift.

8. The method for controlling Hf2CO2 MXene-based nano-optoelectronic devices according to claim 1, characterized in that, The method for applying the in-plane biaxial tensile strain is as follows: transferring or directly growing Hf2CO2 monolayer material on a flexible or stretchable substrate with a predetermined coefficient of thermal expansion, mechanically stretching the substrate to transfer strain to the Hf2CO2 monolayer, or generating a difference in the coefficient of thermal expansion between the substrate and the Hf2CO2 monolayer through temperature control, and transferring strain to the Hf2CO2 monolayer by thermal mismatch.

9. The method for controlling the Hf2CO2 MXene-based nano-optoelectronic device according to claim 1, characterized in that, The aforementioned control method can be implemented alone, or in combination with gate bias control, chemical doping, and heterostructure construction to achieve multi-dimensional synergistic control.

10. A nano-optoelectronic device based on Hf₂CO₂ MXene, characterized in that, The device includes a two-dimensional semiconductor functional layer composed of a single layer of Hf2CO2 material, wherein the carrier transport direction of the two-dimensional semiconductor functional layer is along the zigzag crystal orientation of the Hf2CO2 material, and the single layer of Hf2CO2 material is subjected to an in-plane biaxial tensile strain of 4% to 8%; the nano-optoelectronic device is one of a pn junction diode, a field-effect transistor, or a photodetector.

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