A gate-adjustable high-response photoelectric homojunction field effect device, a manufacturing method thereof and a photoelectric response control method
By introducing a gate-tunable design into a photoelectric homojunction field-effect device, and utilizing the metal gate layer to control the band structure of the channel layer, a high-response photoelectric response is achieved, solving the problem of low photoresponse of existing devices. This is suitable for high-sensitivity detection in the field of intelligent vision.
Patent Information
- Application Number
- CN202411796791.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2025-12-12
- Estimated Expiration
- 2044-12-09
AI Technical Summary
Existing tunable homojunction optoelectronic devices based on two-dimensional materials have low photoresponsivity, making it difficult to meet the requirements of high-sensitivity target detection in the field of intelligent vision.
A gate-tunable high-response opto-homogeneous junction field-effect device was designed. By setting a metal gate layer, an insulating layer and a channel layer on the substrate, and using the voltage of the metal gate layer to adjust the band structure of the channel layer, the dynamic switching of the n-p or n-n homojunction state is realized, thereby enhancing the directional movement of photogenerated carriers.
It achieves a highly sensitive photoelectric response with a maximum photoresponse of 1.0 A/W, significantly improving the photoelectric detection capability of the device, and has a simple structure that is easy to integrate.
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Figure CN119730419B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to two-dimensional optoelectronic devices, and a preparation method and a control method thereof, in particular to a gate-adjustable high-response optoelectronic homojunction field effect device and a preparation method and an optoelectronic response control method thereof. BACKGROUND
[0002] Electrically tunable homojunctions based on ambipolar two-dimensional materials have attracted extensive attention in the field of intelligent vision. Such devices exhibit tunable positive and negative optical response characteristics, which can effectively simulate the behavior of human retinal cells. However, due to the weak light absorption of two-dimensional materials, the optical response of most electrically tunable homojunctions based on two-dimensional materials is still very low, which is difficult to meet the application requirements of high sensitivity target detection in the field of intelligent vision. SUMMARY
[0003] The purpose of the present application is to overcome the deficiencies in the prior art, and the purpose of the present application is to provide a high-sensitivity gate-adjustable high-response optoelectronic homojunction field effect device, the purpose of the present application is to provide a simple and convenient, gate-adjustable high-response optoelectronic homojunction field effect device preparation method, and the purpose of the present application is to provide a gate-adjustable high-response optoelectronic homojunction field effect device based on two-dimensional bipolar semiconductor. The photoelectric response control method.
[0004] Technical scheme: the gate-adjustable high-response optoelectronic homojunction field effect device provided by the application comprises a substrate, a metal gate layer and an insulating layer are arranged on the surface of the substrate, the insulating layer is partially arranged on the metal gate layer, a channel layer is arranged on the surface of the insulating layer, and a source electrode and a drain electrode are arranged on the surface of the channel layer in a spaced manner; the channel layer is made of a material with bipolar field effect characteristics; the channel layer is adjusted to an n - -p or n - -homojunction state by adjusting the voltage of the metal gate layer.
[0005] Further, the source electrode is grounded, and the drain electrode is used to output an optoelectronic signal.
[0006] Further, the substrate is made of monocrystalline silicon or polycrystalline silicon material containing an oxidized insulating layer, and the thickness is 450-550 microns.
[0007] Further, the metal gate layer is made of any one of gold layer, titanium layer, chromium layer and palladium layer, and the thickness is 25-50 nm, the length is less than the length of the channel layer and greater than the length of the source electrode, and the length is preferably 1 / 2 of the length of the channel layer.
[0008] Further, the insulating layer is made of one or more of a silicon dioxide layer, an aluminum oxide layer, a hafnium oxide layer, a hexagonal boron nitride layer, and a zirconium oxide layer, and the thickness is 5-20 nm.
[0009] Furthermore, the channel layer is made of a bipolar two-dimensional semiconductor material with a thickness of 5–25 nm.
[0010] Furthermore, the thickness of both the source and drain electrodes is 20–50 nm.
[0011] The present invention discloses a method for fabricating a gate-tunable high-response optoelectronic homojunction field-effect device, comprising the following steps:
[0012] Step 1: Deposit a metal gate layer on the substrate;
[0013] Step 2: An insulating layer is deposited on the metal gate layer and the substrate using a polyvinyl alcohol dry transfer method;
[0014] Step 3: A trench layer is formed on the surface of the insulation layer using a polyvinyl alcohol dry transfer method;
[0015] Step four: deposit the source and drain electrodes on the channel layer to obtain a high-response opto-homogeneous field-effect device with tunable gate.
[0016] The present invention discloses a photoelectric response control method for a gate-tunable high-response photoelectric homojunction field-effect device. Different intensity light signals are applied to the channel layer. When the gate voltage applied to the metal gate layer is greater than zero, the short-circuit current flowing through the channel layer is positive and flows out from the drain. The short-circuit current increases with the increase of the gate voltage. Scanning the source-drain voltage achieves n... - -n Homojunction Field-Effect Device Function: When the gate voltage applied to the metal gate layer is less than zero, the short-circuit current flowing through the channel layer is negative. The short-circuit current flows in from the drain, and the short-circuit current increases with the increase of the gate voltage. Scanning the source-drain voltage achieves n - -p Homojunction Field Effect Device Functionality.
[0017] Furthermore, the short-circuit current is the current flowing through the channel layer when the drain and source are short-circuited.
[0018] Working principle: A voltage is applied to the channel material through the metal gate layer, causing a change in the band structure of the channel material above the metal gate layer. This results in a built-in electric field between this portion of the channel material and other channel materials not above the metal gate layer, better driving the directional movement of photogenerated carriers generated during illumination, thus increasing the photogenerated current of the channel material and improving sensitivity. Simultaneously, the sign and magnitude of the gate voltage can be adjusted to modify the band structure of the channel material above the metal gate layer, exhibiting an n... - -n homojunction and n - The -p homojunction states exhibit different photoresponses, enabling the gate voltage to modulate the photoresponse of the channel material.
[0019] Beneficial effects: Compared with the prior art, the present invention has the following significant features:
[0020] 1、The obtained high-response photovoltaic homojunction field effect device with adjustable gate can dynamically realize reconfigurable n - -p or n - -n homojunction state, and different gate-adjustable light response characteristics;
[0021] 2、The maximum light response degree is about 1.0A / W, which is obviously greater than the value of 0.1A / W in the previously reported homojunction device, and high-sensitivity detection of the target can be realized;
[0022] 3、The light response can be regulated by the gate voltage to realize high-sensitivity photodetection in different environments, and the device structure is simple and easy to integrate. BRIEF DESCRIPTION OF DRAWINGS
[0023] Figure 1 is a structural schematic diagram of the present application;
[0024] Figure 2 is a front view of the present application;
[0025] Figure 3 is a top view of the present application;
[0026] Figure 4 is a right view of the present application;
[0027] Figure 5 is a bipolar electrical characteristic diagram of the present application;
[0028] Figure 6 is a relationship diagram of different light signals and open-circuit voltage V oc and short-circuit current I sc of the present application;
[0029] Figure 7 is a relationship diagram of different gate voltages and short-circuit current I sc of the present application;
[0030] Figure 8 is a relationship diagram of different light signals and device light response degree R and on / off ratio of the present application when the source-drain voltage is 0V;
[0031] Figure 9 is a relationship diagram of different light signals and device light response degree R and on / off ratio of the present application when the source-drain voltage is 1V. DETAILED DESCRIPTION
[0032] In the following examples, the materials, reagents, etc. used, unless otherwise specified, can be obtained from commercial channels. The experimental methods not specified in the examples are usually carried out according to conventional conditions or according to the conditions recommended by the manufacturer.
[0033] As shown in Figures 1-4 , the metal gate layer 2 of the gate-adjustable high-response optoelectronic homojunction field effect device is on the substrate 1, the insulating layer 3 covers the middle surface of the metal gate layer 2 and the surface of the substrate 1, the upper surface of the insulating layer 3 is flush, and the lower surface is stepped. The surface of the insulating layer 3 has a channel layer 4, and the surface of the channel layer 4 has a source electrode 5 and a drain electrode 6 at both ends, respectively. The substrate 1 is made of monocrystalline silicon or polycrystalline silicon material with an oxidized insulating layer, with a thickness of 450-550 μm, preferably 500 μm. The metal gate layer 2 is made of titanium gold, cadmium gold or palladium gold, with a thickness of 25-50 nm, preferably 30 nm, and a length less than that of the channel layer 4 and greater than that of the source electrode 5. Titanium gold is a layer of titanium and a layer of gold, cadmium gold is a layer of cadmium and a layer of gold, and palladium gold is a layer of palladium and a layer of gold. The insulating layer 3 is made of one or more insulating materials such as a silicon dioxide layer, an aluminum oxide layer, a hafnium oxide layer, a hexagonal boron nitride layer, and a zirconium oxide layer, preferably a hexagonal boron nitride layer, with a thickness of 5-20 nm. The channel layer 4 is composed of a bipolar semiconductor, specifically a two-dimensional semiconductor material such as tungsten diselenide, tungsten disulfide or molybdenum ditelluride, with a band gap range of 0.5-1.5 eV and a thickness of 5-25 nm, preferably 20 nm. The thickness of the source electrode 5 and the drain electrode 6 is 20-50 nm, made of titanium gold, cadmium gold or palladium gold, and the source electrode 5 is grounded. The metal work function of the source electrode 5 and the drain electrode 6 is the middle energy value of the band gap of the channel layer 4.
[0034] The preparation method of the gate-adjustable high-response optoelectronic homojunction field effect device of the embodiment includes the following steps:
[0035] S1, prepare the two-dimensional layered channel layer 4 and the insulating layer 3 by mechanical exfoliation method. Take out the block material with tweezers, place it on a polyvinyl chloride tape, then repeatedly fold the tape to evenly distribute it on the tape, then stick the tape on the insulating substrate 1, and finally gently tear off the tape, leaving the channel layer 4 on the substrate 1. Use the same method to leave the insulating layer 3 on another second substrate 1.
[0036] S2, evaporate the metal gate layer 2 on the third substrate 1. Place the sample to be plated into a vacuum chamber, and vacuumize until the chamber pressure is below -0.1 mPa; first evaporate about 2 nm of titanium as an adhesion layer at a rate of , then evaporate about 30 nm of gold at a rate of .
[0037] S3, transfer the channel layer 4 and the insulating layer 3 prepared in step S1 to the substrate 1 containing the metal gate layer 2 obtained in step S2 by polyvinyl alcohol dry transfer method.
[0038] S4, the source 5 and the drain 6 are prepared on the surface of the channel layer 4 prepared in step S3 by using electron beam evaporation method. The sample to be plated is put into a vacuum chamber, and vacuum is drawn until the chamber pressure is below -0.1 mPa. First, about 5 nm of titanium is plated as an adhesion layer at a speed of , and then about 45 nm of gold is plated at a speed of .
[0039] The channel layer 4 of the gate-adjustable high-response photoelectric homojunction field effect device can be regulated to be n - -p and n - -n homojunction under the bias of the gate voltage, and further realizes different states of the homojunction under the operation of different positive and negative gate voltages, so as to determine the on or off state of the current of the device under a specific drain voltage. The specific regulation mode is as shown in Figure 5 : the device realizes n - -n homojunction field effect device function when the gate voltage is greater than zero and the source-drain voltage is scanned; and realizes n - -p homojunction field effect device function when the gate voltage is less than zero and the source-drain voltage is scanned. Thus, the device can realize the functions of n - -n homojunction field effect device and n - -p homojunction field effect device under different electrical operations based on a single device.
[0040] The gate voltage V1 is applied to the metal gate layer 2, and the light signals P1, P2, P3, P4, P5, P6 and P7 are applied to the channel layer 4, and the short-circuit current I sc flowing through the drain 6 and the open-circuit voltage V oc appearing between the source and the drain are recorded respectively, and the relationship diagram of the short-circuit current I sc and the open-circuit voltage V oc and the incident light pulse is obtained. The gate voltage V1 is applied to the metal gate layer 2, and the light signals P1, P2, P3, P4, P5, P6 and P7 are applied to the channel layer 4, and the short-circuit current I sc flowing through the drain 6 and the open-circuit voltage V oc appearing between the source and the drain are recorded respectively, and the relationship diagram of the short-circuit current I sc and the open-circuit voltage V oc and the incident light pulse is obtained. P1=0.13 nW, P2=1.30 nW, P3=13.0 nW, P4=26.0 nW, P5=130 nW, P6=260 nW, and P7=1.30 μW.
[0041] The photoelectric response of the device is regulated by the gate voltage to realize high response. In the state of n - -p homojunction, the relationship between different light signals and the short-circuit current I sc and the open-circuit voltage V oc is as shown inFigure 6 The short circuit current I sc and the open circuit voltage V oc increases with the increase of the light signal power, the maximum short circuit current I sc reaches the order of microampere, the maximum open circuit voltage V oc reaches 0.48V.
[0042] The light signal P5 is applied to the channel layer, and when the bias applied to the metal gate is V1, V2, V3, V4, V5, V6 (V1 sc , the short circuit current I sc flowing through the drain 6 is recorded respectively, and the relationship diagram of the device short circuit current I sc and the gate voltage is obtained. V1=-5V, V2=-3V, V3=-1V, V4=1V, V5=3V, V6=5V.
[0043] Under the condition that the light signal power is constant, the relationship of the device short circuit current I sc and the gate voltage is shown in Figure 7 , the device short circuit current I sc increases with the increase of the gate voltage, and reverses with the reverse of the gate voltage, indicating that the photoelectric response of the device can be regulated by the voltage applied by the metal gate layer 2.
[0044] When the bias applied to the metal gate layer 2 is V1, the short circuit current I sc at the end of the drain 6 generated by applying light signals P1, P2, P3, P4, P5, P6, P7 to the channel layer 4 is compared with the current at the end of the drain 6 when no light signal is applied, and the change relationship of the gate-regulated high-response photoelectric homojunction field effect device light responsivity R and the on / off ratio with the incident light signal is obtained.
[0045] The relationship of the light signal with the device light responsivity R and the on / off ratio in the state of the n - -p homojunction is shown in Figures 8-9 , wherein, Figure 8 is the relationship diagram when the metal source-drain voltage is 0V, and Figure 9 is the relationship diagram when the metal source-drain voltage is 1V. It can be seen that the device light responsivity R increases with the increase of the light signal power, and the on / off ratio almost remains unchanged with the increase of the light signal power. At the same time, by comparing Figure 8 and Figure 9 , the on / off ratio decreases with the increase of the source-drain voltage, and the device light responsivity R increases with the increase of the source-drain voltage, and the highest reaches 1.0A / W, indicating that the device realizes high photoelectric response.
Claims
1. A gate-tunable, high-response opto-homogeneous field-effect device, characterized in that: The system includes a substrate (1), on which a metal gate layer (2) and an insulating layer (3) are disposed. The insulating layer (3) is partially disposed on the metal gate layer (2). A channel layer (4) is disposed on the surface of the insulating layer (3). A source electrode (5) and a drain electrode (6) are disposed at intervals on the surface of the channel layer (4). The channel layer (4) is made of a material with bipolar field-effect characteristics. The voltage of the channel layer (4) is adjusted to n by adjusting the voltage of the metal gate layer (2). - -p or n - -n Homojunction state; The source (5) is grounded, and the drain (6) is used to output photoelectric signals; When optical signals of different intensities are applied to the channel layer (4), and the gate voltage applied to the metal gate layer (2) is greater than zero, the short-circuit current flowing through the channel layer (4) is positive, and the short-circuit current flows out from the drain (6). The short-circuit current increases with the increase of the gate voltage, and the scanning source-drain voltage achieves n - -n Homojunction Field Effect Device Function; When the gate voltage applied to the metal gate layer (2) is less than zero, the short-circuit current flowing through the channel layer (4) is negative. The short-circuit current flows in from the drain (6), and the short-circuit current increases with the increase of the gate voltage. The scanning source-drain voltage realizes n - -p homojunction field-effect device functionality; The short-circuit current is the current flowing through the channel layer (4) when the drain (6) and source (5) are short-circuited.
2. The gate-tunable high-response photoelectric homojunction field-effect device according to claim 1, characterized in that: The substrate (1) is made of monocrystalline silicon or polycrystalline silicon containing an oxide insulating layer, with a thickness of 450~550μm.
3. The gate-tunable high-response photoelectric homojunction field-effect device according to claim 1, characterized in that: The metal gate layer (2) is made of a composite of gold, titanium, chromium and palladium layers, with a thickness of 25~50nm and a length less than that of the channel layer (4) and greater than that of the source layer (5).
4. The gate-tunable high-response photoelectric homojunction field-effect device according to claim 1, characterized in that: The insulating layer (3) is made of one or more of the following: silicon dioxide layer, aluminum oxide layer, hafnium oxide layer, hexagonal boron nitride layer, and zirconium oxide layer, with a thickness of 5~20nm.
5. The gate-tunable high-response photoelectric homojunction field-effect device according to claim 1, characterized in that: The channel layer (4) is made of a two-dimensional semiconductor material with bipolarity and has a thickness of 5~25nm.
6. The gate-tunable high-response photoelectric homojunction field-effect device according to claim 1, characterized in that: The thickness of the source (5) and drain (6) is 20~50nm.
7. A method for fabricating a gate-tunable high-response opto-homogeneous field-effect device according to any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Deposit a metal gate layer (2) on the substrate (1). Step 2: An insulating layer (3) is formed on the metal gate layer (2) and the substrate (1) by a polyvinyl alcohol dry transfer method. Step 3: A trench layer (4) is formed on the surface of the insulating layer (3) by a polyvinyl alcohol dry transfer method. Step 4: Deposit source (5) and drain (6) on channel layer (4) to obtain a high-response opto-homogeneous field-effect device with tunable gate.
Citation Information
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