A two-dimensional material photoelectric detector based on quantum tunneling mechanism

Abstract

The application relates to a two-dimensional material photoelectric detector based on a quantum tunneling mechanism, which comprises a gate, an insulating layer, a P-type layer, an N-type layer, a protective layer, a source electrode lead-out end and a drain electrode lead-out end. The P-type layer, the N-type layer and the protective layer are mechanically exfoliated and dry-transferred on the gate and the insulating layer in a sequence from bottom to top, the P-type layer is a wide-bandgap two-dimensional material, and the N-type layer is a narrow-bandgap two-dimensional material; photons are incident from the top, the anode lead-out end on the P-type layer is connected with the positive pole of a power supply, the drain electrode lead-out end on the N-type layer is connected with the negative pole of the power supply, and the photons are absorbed by a PN junction space charge region. The application has the advantages of simple process, compact design, and can greatly reduce dark current and sub-threshold swing, improve rectification ratio and switching ratio under a high-temperature working environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photoelectric detectors, and particularly relates to a two-dimensional material photoelectric detector based on a quantum tunneling mechanism. BACKGROUND

[0002] Two-dimensional semiconductors have attracted great attention due to their interesting structures and rich layer-number-dependent physical properties, which also show high potential in the next generation of optoelectronic and electronic devices. In addition, two-dimensional layered materials do not contain dangling bonds, thus making it possible to fabricate van der Waals heterostructures by their combination. The resulting van der Waals heterostructures with band alignment realize various functions and thus can be used for lasers, field effect transistors, memories, solar cells, logic rectifiers and photoelectric detectors. So far, there are three possible types of band alignment of heterostructures based on two-dimensional semiconductor materials: type I - across the saddle, type II - staggered and type III - broken gap. Compared with the other two types of band alignment, the type III heterostructure has non-overlapping band gaps between the two semiconductors, and is widely used to design various high-speed, low-power devices due to the charge transport through the heterostructure by interband quantum tunneling. Such quantum tunneling can also greatly increase the drain current.

[0003] Broken gap van der Waals heterostructures based on various combinations of 2D materials have been realized by different modulation methods such as gate coupling, thickness modulation, chemical doping, etc. These heterostructure devices such as hetero-tunnel field effect transistors and Esaki diodes are of great interest due to their tunneling mechanism which can be used as hetero-tunnel field effect transistors. Designing devices with large rectification ratio and high on-off ratio helps the development of multi-valued logic and binary inverters. In addition, for van der Waals heterostructure diodes, the rectification behavior is not only controlled by the Fermi level difference, but also by the valence band or conduction band offset between the two stacked materials. However, van der Waals heterostructures usually have a relatively small conduction band offset, in which the reverse and forward currents will increase synchronously, which will limit the rectification behavior of the device. Therefore, the on-current rectification ratio of the diode and the on-off ratio of the transistor cannot be obtained simultaneously in the same hetero-diode. In addition, for photoelectric detectors, the increased drain current means a large dark current, which will further result in a low photocurrent on-off ratio. SUMMARY

[0004] The purpose of the present application is to provide a two-dimensional material photoelectric detector based on a quantum tunneling mechanism, which solves the defects that the on-current rectification ratio of the diode and the on-off ratio of the transistor cannot be obtained simultaneously in the same hetero-diode in the prior art, and for photoelectric detectors, the increased drain current means a large dark current, which will further result in a low photocurrent on-off ratio.

[0005] To achieve the above object, the technical scheme of the present application is:

[0006] A two-dimensional material photoelectric detector based on quantum tunneling mechanism, comprising a gate electrode, an insulating layer, a P-type layer, an N-type layer, a protective layer, an anode lead-out end and a cathode lead-out end; the anode lead-out end and the cathode lead-out end are arranged on the gate electrode and the insulating layer as a bottom electrode; the P-type layer, the N-type layer and the protective layer are sequentially arranged on the insulating layer in the order from bottom to top.

[0007] The P-type layer is a wide-bandgap two-dimensional material made of tungsten diselenide or molybdenum disulfide, and the N-type layer is a narrow-bandgap two-dimensional material made of palladium diselenide or platinum diselenide.

[0008] The gate electrode is a conductive layer made of high-doped P-type silicon, and the doping concentration of boron is 5×10 17 ~ 5×10 18 per cubic centimeter; alternatively, the gate electrode is a conductive layer made of graphene; the thickness of the gate electrode ranges from 10 nanometers to 200 nanometers.

[0009] The insulating layer is an insulating material made of silicon dioxide, aluminum trioxide or hexagonal boron nitride, and the thickness of the insulating layer ranges from 10 nanometers to 200 nanometers.

[0010] The P-type layer, the N-type layer and the protective layer are sequentially transferred to the insulating layer from bottom to top by mechanical exfoliation dry method.

[0011] The protective layer is made of oxidation-resistant material hexagonal boron nitride or PMMA A5 photoresist, and the thickness of the protective layer ranges from 10 nanometers to 200 nanometers.

[0012] The thickness of the P-type layer ranges from 10 nanometers to 200 nanometers; the thickness of the N-type layer ranges from 10 nanometers to 200 nanometers.

[0013] The anode lead-out end and the cathode lead-out end are evaporated on the gate electrode and the insulating layer as a bottom electrode.

[0014] The anode lead-out end is a chromium-gold double-layer electrode or a titanium-gold double-layer electrode; chromium or titanium is a contact layer in contact with the insulating layer, and gold is a metal conductive layer.

[0015] The cathode lead-out end is a chromium-gold double-layer electrode or a titanium-gold double-layer electrode; chromium or titanium is a contact layer in contact with the insulating layer, and gold is a metal conductive layer.

[0016] In the chromium-gold double-layer electrode, the thickness of chromium is 5 nanometers to 100 nanometers, and the thickness of gold is 5 nanometers to 100 nanometers; in the titanium-gold double-layer electrode, the thickness of titanium is 5 nanometers to 100 nanometers, and the thickness of gold is 5 nanometers to 100 nanometers.

[0017] The beneficial effects of the present application are: 1. A discontinuous gap van der Waals heterostructure is proposed, which uses a wide-bandgap P-type two-dimensional material combined with a narrow-bandgap N-type two-dimensional material to form a large conduction band offset to suppress the forward current. In this case, the narrow-bandgap two-dimensional material with high carrier concentration and high mobility can be used as an effective carrier selective contact for reverse tunneling electrons, and there is almost no heterojunction interface barrier. Therefore, the rectification ratio of the heterodiode can be greatly improved. Under illumination, the forward photocurrent can be significantly improved by light-controlled tunneling transport. In addition, the photo-generated tunneling electrons in the wide-bandgap two-dimensional material accumulation region can quickly recombine with the majority hole carriers in the opposite direction, reducing the interface trapping effect and significantly improving the response speed; 2. By using the gate to regulate the Fermi level of the lower wide-bandgap two-dimensional material, and at the same time by using the bias voltage to regulate the Fermi level of the wide-bandgap and narrow-bandgap two-dimensional materials at the source and drain, the energy band matching of the wide-bandgap and narrow-bandgap two-dimensional materials at the source and drain can be jointly regulated, which can switch from a type II heterojunction to a type III heterojunction, form a band-to-band quantum tunneling channel, switch from ultra-low dark current to ultra-high dark current, and form ultra-high rectification ratio and low sub-threshold swing. Under illumination, photons will trigger the photo-induced tunneling mechanism of the heterojunction to produce a large photocurrent and form an excellent optical switching ratio. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic diagram of the cross-sectional structure of the present application;

[0019] Figure 2 is a dark current versus source-drain voltage relationship of an embodiment of the present application, with the vertical coordinate being an exponential coordinate;

[0020] Figure 3 is a dark current versus gate voltage relationship in an embodiment of the present application, with the vertical coordinate being an exponential coordinate;

[0021] Figure 4 is a photocurrent versus source-drain voltage relationship in an embodiment of the present application, with the vertical coordinate being an exponential coordinate.

[0022] In the figure: 1-gate; 2-insulating layer; 3-P-type layer; 4-N-type layer; 5-protection layer; 6-anode lead-out end; 7-cathode lead-out end. DETAILED DESCRIPTION

[0023] The present application will be further described below in conjunction with the drawings. The drawings are only used for illustrative explanation and cannot be understood as limiting the patent.

[0024] In order to more simply illustrate the present embodiment, some parts that are well known to those skilled in the art but are not related to the main content of the present creation will be omitted in the drawings or description. In addition, some parts will be omitted, enlarged or reduced in the drawings for the convenience of description, but this does not represent the size or the entire structure of the actual product.

[0025] The application discloses a two-dimensional material photoelectric detector based on a quantum tunneling mechanism, which comprises a gate electrode 1, an insulating layer 2, a P-type layer 3, an N-type layer 4, a protective layer 5, an anode lead-out end 6 and a cathode lead-out end 7. Figure 1 As shown in the figure, the gate electrode 1, the insulating layer 2, the P-type layer 3, the N-type layer 4, the protective layer 5, the anode lead-out end 6 and the cathode lead-out end 7 are sequentially arranged from bottom to top.

[0026] The gate electrode 1 is a conductive layer made of high-doped P-type silicon, and the doping concentration of boron is 5*10 17 ~ 5*10 18 Each cubic centimeter; or the gate electrode 1 is a conductive layer made of graphene; the thickness of the gate electrode 1 ranges from 10 nanometers to 200 nanometers.

[0027] The insulating layer 2 is an insulating material made of silicon dioxide, di-aluminum trioxide or hexagonal boron nitride, and the thickness of the insulating layer 2 ranges from 10 nanometers to 200 nanometers.

[0028] The silicon wafer and the gate electrode 1 and the insulating layer 2 are cleaned step by step using acetone, isopropyl alcohol and deionized water; PMMA A5 photoresist is spin-coated by using a spin coater and then dried; the bottom electrode pattern including the anode lead-out end 6 and the cathode lead-out end 7 is photoetched by using electron beam lithography and then developed.

[0029] The bottom electrode including the anode lead-out end 6 and the cathode lead-out end 7 is completed by using electron beam evaporation and then stripping.

[0030] The anode lead-out end 6 is a chromium-gold double-layer electrode or a titanium-gold double-layer electrode, the chromium or titanium is a contact layer in contact with the insulating layer 2, and the gold is a metal conductive layer.

[0031] The cathode lead-out end 7 is a chromium-gold double-layer electrode or a titanium-gold double-layer electrode, the chromium or titanium is a contact layer in contact with the insulating layer 2, and the gold is a metal conductive layer.

[0032] In the chromium-gold double-layer electrode, the thickness of the chromium ranges from 5 nanometers to 100 nanometers, and the thickness of the gold ranges from 5 nanometers to 100 nanometers; in the titanium-gold double-layer electrode, the thickness of the titanium ranges from 5 nanometers to 100 nanometers, and the thickness of the gold ranges from 5 nanometers to 100 nanometers.

[0033] After the fabrication of the anode lead-out end 6 and the cathode lead-out end 7 is completed, the P-type layer 3, the N-type layer 4 and the protective layer 5 are sequentially arranged on the insulating layer 2 in the order from bottom to top.

[0034] The P-type layer 3 is a wide-band-gap two-dimensional material made of tungsten diselenide or molybdenum disulfide, and the thickness ranges from 10 nanometers to 200 nanometers; the N-type layer 4 is a narrow-band-gap two-dimensional material made of palladium diselenide or platinum diselenide, and the thickness ranges from 10 nanometers to 200 nanometers.

[0035] The protective layer 5 is made of the oxidation-resistant material hexagonal boron nitride or PMMA A5 photoresist, and the thickness of the protective layer 5 ranges from 10 nanometers to 200 nanometers.

[0036] The P-type layer 3, N-type layer 4, and protective layer 5 are transferred sequentially from bottom to top onto the insulating layer 2 using a dry mechanical peeling method.

[0037] Preferably, a P-type layer 3 of tungsten diselenide with a thickness ranging from 10 nm to 200 nm is transferred using a transfer platform; then, an N-type layer 4 of platinum diselenide with a thickness ranging from 10 nm to 200 nm is transferred using a transfer platform; finally, a protective layer 5 of hexagonal boron nitride with a thickness ranging from 10 nm to 200 nm is transferred using a transfer platform.

[0038] The photodetector of this invention was finally manufactured.

[0039] like Figure 2 The figure shows the relationship between the dark current and source-drain voltage of the photodetector of this invention at a temperature of 300 Kelvin. The dark current is as low as 10 Kelvin. -11 Ampere, rectification ratio up to 10 4 .

[0040] like Figure 3 The figure shows the relationship between the dark current and the gate voltage of the photodetector of this invention at a temperature of 300 Kelvin. The subthreshold swing is as low as 180 millivolts per order of magnitude.

[0041] like Figure 4 The figure shows the relationship between the photocurrent and source-drain voltage of the photodetector of this invention at a temperature of 300 Kelvin. Under 2.4 mW 520 nm laser irradiation, the optical on / off ratio exceeds 500.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. All equivalent changes and modifications made within the scope of the claims of this invention should be considered within the technical scope of this invention.

Claims

1. A two-dimensional material photodetector based on quantum tunneling mechanism, comprising a gate electrode (1), an insulating layer (2), a P-type layer (3), an N-type layer (4), a protective layer (5), an anode lead (6), and a cathode lead (7), characterized in that: the anode lead (6) and the cathode lead (7) are arranged on the gate electrode (1) and the insulating layer (2) as bottom electrodes, and the P-type layer (3), the N-type layer (4), and the protective layer (5) are sequentially arranged on the insulating layer (2) from bottom to top; the P-type layer (3) is a wide-bandgap two-dimensional material made of tungsten diselenide or molybdenum disulfide, and the N-type layer (4) is a narrow-bandgap two-dimensional material made of palladium diselenide or platinum diselenide; the Fermi level of the P-type two-dimensional material of the lower layer is controlled by using the gate electrode, and the Fermi levels of the P-type and N-type two-dimensional materials of the wide-bandgap and narrow-bandgap on the source and drain are controlled by bias voltage, thereby jointly controlling the energy band matching of the P-type and N-type two-dimensional materials of the wide-bandgap and narrow-bandgap on the source and drain, switching from a type II heterojunction to a type III heterojunction, forming a band inter quantum tunneling channel, switching from ultra-low dark current to ultra-high dark current, forming an ultra-large rectification ratio and a low sub-threshold swing; under light irradiation, photons trigger the photo-induced tunneling mechanism of the heterojunction to generate a large photocurrent and form an excellent light switch ratio. Alternatively, the gate electrode (1) is a conductive layer made of graphene; the thickness of the gate electrode (1) ranges from 10 nanometers to 200 nanometers. The insulating layer (2) is an insulating material made of silicon dioxide, aluminum trioxide, or hexagonal boron nitride; the thickness of the insulating layer (2) ranges from 10 nanometers to 200 nanometers.

2. The two-dimensional material photodetector based on quantum tunneling mechanism of claim 1, wherein, The gate electrode (1) is a conductive layer made of highly P-doped silicon, with a boron doping concentration of 5 x 1019 atoms per cubic centimeter. 10 17 ~5× 10 18 atoms per cubic centimeter; The P-type layer (3), the N-type layer (4), and the protective layer (5) are sequentially transferred onto the insulating layer (2) by mechanical exfoliation dry method.

3. The two-dimensional material photodetector based on quantum tunneling mechanism of claim 1, wherein, The protective layer (5) is made of an oxidation-resistant material, hexagonal boron nitride, or PMMA A5 photoresist; the thickness of the protective layer (5) ranges from 10 nanometers to 200 nanometers.

4. The two-dimensional material photodetector based on quantum tunneling mechanism of claim 1, wherein: The thickness of the P-type layer (3) ranges from 10 nanometers to 200 nanometers; the thickness of the N-type layer (4) ranges from 10 nanometers to 200 nanometers.

5. The two-dimensional material photodetector based on quantum tunneling mechanism of claim 4, wherein: The anode lead (6) and the cathode lead (7) are evaporated on the gate electrode (1) and the insulating layer (2) as bottom electrodes.

6. The two-dimensional material photodetector based on quantum tunneling mechanism of claim 4, wherein: The anode lead (6) is a chromium-gold double-layer electrode or a titanium-gold double-layer electrode; chromium or titanium is a contact layer in contact with the insulating layer (2), and gold is a metal conductive layer; 7. The two-dimensional material photodetector based on quantum tunneling mechanism of claim 1, wherein: The cathode lead (7) is a chromium-gold double-layer electrode or a titanium-gold double-layer electrode; chromium or titanium is a contact layer in contact with the insulating layer (2), and gold is a metal conductive layer.

8. The two-dimensional material photodetector based on quantum tunneling mechanism according to claim 7, wherein: In the chromium-gold double-layer electrode, the thickness of chromium ranges from 5 nanometers to 100 nanometers, and the thickness of gold ranges from 5 nanometers to 100 nanometers; in the titanium-gold double-layer electrode, the thickness of titanium ranges from 5 nanometers to 100 nanometers, and the thickness of gold ranges from 5 nanometers to 100 nanometers. ​ 9. The two-dimensional material photodetector based on quantum tunneling mechanism according to claim 8, wherein: ​

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