A hybrid-dimension material based composite mosfet photodetector

Abstract

The application discloses a kind of composite MOSFET photoelectric detectors based on mixed-dimensional material, belong to photoelectric detection field.The built-in electric field in the top PN junction of the detector makes a kind of photo-generated carrier be collected by graphene, so as to influence the junction carrier of bottom PN junction by high-k hexagonal boron nitride, and a MOSFET structure driven by light is formed;PbSe quantum dots expand the wavelength range of the device.The built-in electric field formed by bottom PN junction makes photo-generated carrier separate and produce intrinsic response;One-dimensional material can detect polarized light, and the cross-sectional area is small, effectively suppresses dark current.At the same time, the two PN junctions can be controlled by the top gate, so that the device works in the amplification zone of MOSFET, and the light response is linearly amplified.The application effectively avoids the occurrence of light gating, realizes polarization, wide band, high sensitivity, high-speed detector.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of photoelectric detection, and particularly relates to a composite MOSFET photoelectric detector based on a mixed-dimensional material. BACKGROUND

[0002] Photoelectric detectors play an extremely important role in daily life and production, whether they are used for photoelectric imaging or optical communication. The function of a photoelectric detector is to convert the optical signals it collects into electrical signals that can be processed by standard electronic equipment. Infrared photoelectric detectors have been the focus of international research due to their wide range of applications in biological imaging, thermal imaging, health monitoring, night vision, and optical communication. In semiconductor photoelectric devices, silicon is the most commonly used material. Silicon-based photoelectric detectors have a relatively mature process on existing complementary metal oxide semiconductor imaging devices, which makes silicon-based photoelectric devices small and scalable, greatly reducing manufacturing costs, while also having low power consumption, high efficiency, and other characteristics. They have been widely used as the main force for visible and near-infrared photoelectric detection in fields such as aerospace, security, medical care, and monitoring. However, since silicon is an indirect bandgap semiconductor material with a bandgap of about 1.12 eV (corresponding to an absorption cutoff wavelength of about 1.1 μm), it limits the detection of near-infrared wavelengths by silicon. In order to expand the response band of photoelectric detectors, smaller bandgap semiconductor materials such as epitaxially grown mercury cadmium telluride, indium gallium arsenide, indium antimonide, and type II superlattices are often used. These semiconductor materials can well cover the near-infrared to far-infrared spectral range that silicon cannot detect, but the use of molecular beam epitaxy or metal organic chemical vapor deposition equipment greatly increases the manufacturing cost. In addition, infrared photoelectric devices made of these materials generally need to work at low temperatures to maintain low noise and high sensitivity. At the same time, due to the problem of lattice mismatch, these traditional infrared semiconductor materials are difficult to be compatible with silicon using mature complementary metal oxide semiconductor technology, which makes it difficult to be highly integrated. Traditional photoelectric detection materials have been difficult to meet the requirements of silicon process compatibility, low manufacturing cost, and no need for low-temperature operation. Research based on new mechanisms and new materials is a technical problem that needs to be solved urgently for the development of new high-performance infrared photoelectric devices.

[0003] Currently, infrared quantum dot heterojunction photoelectric detectors use quantum dot materials to prepare a colloidal thin film as an infrared sensitive layer, and two-dimensional materials such as graphene as a conductive channel. The quantum dot material absorbs incident light, generates photo-generated carriers, and the electron-hole pairs are separated at the two-dimensional / quantum dot interface. The carriers enter the conductive channel graphene to form a photocurrent, achieving photoelectric detection. However, due to the single two-dimensional material channel, the device has a high dark current, which easily obscures the weak light carrier signal. In addition, the response is affected by the device light gating, resulting in a slow response speed, and the detector has a single dimension, which can only perform intensity detection. SUMMARY

[0004] The application aims to solve the problems of poor weak light detection performance, limited detection dimension, slow response speed, small detection wavelength range of photodetector and large dark current of traditional two-dimensional material heterojunction.

[0005] The application adopts two PN junctions made in the vertical direction, the top PN junction is composed of graphene and quantum dots, and the bottom PN junction is composed of one-dimensional material and two-dimensional material. The built-in electric field in the top PN junction makes a kind of photo-generated carrier be collected by graphene with lower state density, and then the high-k hexagonal boron nitride (hBN) affects the carrier in the junction region of the bottom PN junction, forming a MOSFET structure driven by light; the atomic-level flat surface and the non-suspended bond characteristics of hexagonal boron nitride can significantly reduce the interface defects and charge scattering of the dielectric layer and the adjacent material, avoiding the non-radiative recombination of the carrier in the transmission process; and the atomic-level thickness and high-k value of hexagonal boron nitride make the photo-generated carrier have high field effect regulation efficiency on the bottom junction region; the narrow band gap characteristics and strong light absorption capacity of PbSe quantum dots expand and enhance the detection wavelength range and detection sensitivity of the device. The built-in electric field formed by the bottom PN junction makes the photo-generated carrier separate and produce intrinsic response, and works as a channel under reverse bias; the one-dimensional material can detect polarized light with a wavelength range in the mid-wave infrared (3-5 μm) due to the anisotropy of its structure, which expands the response dimension of the device; and the effective electrical area of the cross section of the one-dimensional material is small, which, combined with the PN junction channel working under reverse bias, will further suppress the dark current; at the same time, the vertical direction junction capacitance can be controlled through the top gate, so that the device works in the amplification region of MOSFET, and the response is regulated to achieve maximum amplification effect. The application combines the photovoltaic effect (Photovoltaic Effect) of mixed dimension material and the amplification mechanism of MOSFET to realize a compact polarized, wide-band, high-sensitivity and high-speed detector.

[0006] Therefore, the technical scheme of the application is a composite MOSFET photodetector based on mixed dimension material, characterized in that the structure of the photodetector comprises: a silicon dioxide substrate, a source metal electrode, a drain metal electrode, MoSe2 two-dimensional material, PbSe nanowire one-dimensional material, hexagonal boron nitride, graphene, PbSe quantum dots, and a top gate metal electrode.

[0007] The source metal electrode and the drain metal electrode are arranged on both sides of the upper surface of the silicon dioxide substrate, and the first layer of MoSe2 two-dimensional material is arranged between the source metal electrode and the drain metal electrode, the first layer of MoSe2 two-dimensional material is not in contact with the source metal electrode and the drain metal electrode, and hollow isolation is adopted; the second layer of MoSe2 two-dimensional material is arranged on the upper surface of the source metal electrode and extends inward to be connected with the first layer of MoSe2 two-dimensional material, forming a stepped shape; the PbSe nanowire one-dimensional material is arranged on the upper surface of the first layer of MoSe2 two-dimensional material and the drain metal electrode, and the PbSe nanowire one-dimensional material is in the form of a strip and is arranged at intervals; the upper surface of the first layer of MoSe2 two-dimensional material is sequentially stacked with hexagonal boron nitride, graphene, PbSe quantum dots and a top gate metal electrode.

[0008] Further, the source metal electrode, the drain metal electrode and the top gate metal electrode are made of the same material and have a thickness of 35-45 nm.

[0009] Further, each layer of MoSe2 two-dimensional material has a thickness of 10-20 nm.

[0010] Further, the PbSe nanowire one-dimensional material has a thickness of 20-30 nm, a width of 20-30 nm and a length of 40-50 pm.

[0011] Further, the hexagonal boron nitride has a thickness of 20-30 nm.

[0012] Further, the graphene has a thickness of 0.335 nm.

[0013] Further, the PbSe quantum dots have a thickness of 200-250 nm.

[0014] The application adopts two PN junctions stacked in the vertical direction, the top PN junction is composed of graphene and PbSe quantum dots, and the bottom PN junction is composed of PbSe nanowire one-dimensional material and MoSe2 two-dimensional material. When incident light is irradiated, the built-in electric field in the top PN junction drives the photogenerated carrier separation and is collected by the graphene with low state density. The changing charge concentration in the graphene produces a field effect, which affects the carrier distribution of the junction region of the bottom PN junction through the high-k hexagonal boron nitride, forming a photo-driven field effect transistor structure; the high-k value of the hexagonal boron nitride makes the photogenerated carrier have high field effect regulation efficiency on the bottom junction region; the narrow band gap characteristic and strong light absorption capacity of the PbSe quantum dots expand and enhance the detection wavelength range and detection sensitivity of the device. The built-in electric field formed by the bottom PN junction makes the photogenerated carrier separate and produce intrinsic response, and works as a channel under reverse bias; the PbSe nanowire one-dimensional material can detect polarized light due to the anisotropy of its structure; and the cross-section effective electrical area of the one-dimensional material is small, which, combined with the PN junction channel working under reverse bias, will further suppress the dark current; at the same time, the vertical direction junction capacitance can be controlled through the top gate, so that the device works in the amplification region of the MOSFET, and the light response is linearly amplified. The application combines the photovoltaic effect of the mixed heterojunction and the amplification mechanism of the MOSFET to realize the polarization, wide band, high sensitivity and high speed detector. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 FIG. 1 is a schematic diagram of the cross-sectional structure of the detector of the application (along the horizontal direction).

[0016] Figure 2 FIG. 2 is a schematic diagram of the cross-sectional structure of the detector of the application (along the vertical direction).

[0017] Figure 3 FIG. 3 is a top view of the detector of the application.

[0018] Figure 4 FIG. 4 is a performance comparison diagram of the detector of the application and a conventional device.

[0019] Figure 5 FIG. 5 is a graph of the relationship between the response wavelength and the responsivity of the detector of the application. DETAILED DESCRIPTION

[0020] As shown in Figure 1 , Figure 2 , Figure 3 : a composite MOSFET photodetector based on mixed-dimensional materials, the structure of which comprises: a silicon dioxide substrate, a source metal electrode, a drain metal electrode, a MoSe2 two-dimensional material, a PbSe nanowire one-dimensional material, a hexagonal boron nitride, graphene, PbSe quantum dots, and a top gate metal electrode.

[0021] The source metal electrode, the drain metal electrode and the MoSe2 two-dimensional material at the bottom are on the silicon dioxide substrate; the MoSe2 two-dimensional material at the middle is on the source metal electrode; the PbSe nanowire one-dimensional material is on the drain metal electrode; the hexagonal boron nitride is on the PbSe nanowire one-dimensional material; the graphene is on the hexagonal boron nitride; the PbSe quantum dot is on the graphene; and the top gate metal electrode is on the PbSe quantum dot.

[0022] The source metal electrode and the drain metal electrode at the bottom are on the silicon dioxide substrate, and the thickness of the metal electrode is 35nm-45nm;

[0023] The MoSe2 two-dimensional material at the bottom is on the silicon dioxide substrate, and the thickness of the MoSe2 two-dimensional material is 10nm-20nm;

[0024] The MoSe2 two-dimensional material at the middle is on the source metal electrode, and the thickness of the MoSe2 two-dimensional material is 10nm-20nm;

[0025] The PbSe nanowire one-dimensional material is on the drain metal electrode, and the thickness of the PbSe nanowire one-dimensional material is 20nm-30nm;

[0026] The width of the PbSe nanowire one-dimensional material is 20nm-30nm.

[0027] The length of the PbSe nanowire one-dimensional material is 40μm-50μm.

[0028] The hexagonal boron nitride is on the PbSe nanowire one-dimensional material, and the thickness of the hexagonal boron nitride is 20nm-30nm;

[0029] The graphene is on the hexagonal boron nitride, and the thickness of the graphene is 0.335nm;

[0030] The PbSe quantum dot is on the graphene, and the thickness of the PbSe quantum dot is 200nm-250nm;

[0031] The top gate metal electrode is on the PbSe quantum dot, and the thickness of the top gate metal electrode is 35nm-45nm.

[0032] The preparation method of the composite MOSFET photoelectric detector based on the mixed-dimensional material is as follows:

[0033] S1. providing a silicon dioxide substrate;

[0034] S2. manufacturing a source metal electrode and a drain metal electrode on the silicon dioxide substrate;

[0035] S3. manufacturing a bottom MoSe2 two-dimensional material on the silicon dioxide substrate;

[0036] S4. Fabricating middle MoSe2 two-dimensional material on the source metal electrode;

[0037] S5. Fabricating PbSe nanowire one-dimensional material on the drain metal electrode;

[0038] S6. Fabricating hexagonal boron nitride on the PbSe nanowire one-dimensional material;

[0039] S7. Fabricating graphene on the hexagonal boron nitride;

[0040] S8. Spin-coating PbSe quantum dots on the graphene;

[0041] S9. Fabricating top-gate metal electrode on the PbSe quantum dots.

[0042] The composite MOSFET photoelectric detector based on the mixed-dimensional material provided by the application is specifically as follows:

[0043] The source metal electrode and the drain metal electrode are on the silicon dioxide substrate, and the thickness of the metal electrode is 35 nm;

[0044] The bottom MoSe2 two-dimensional material is on the silicon dioxide substrate, and the thickness of the MoSe2 two-dimensional material is 10 nm;

[0045] The middle MoSe2 two-dimensional material is on the source metal electrode, and the thickness of the MoSe2 two-dimensional material is 10 nm;

[0046] The PbSe nanowire one-dimensional material is on the drain metal electrode, and the thickness of the PbSe nanowire one-dimensional material is 30 nm;

[0047] The hexagonal boron nitride is on the PbSe nanowire one-dimensional material, and the thickness of the hexagonal boron nitride is 30 nm;

[0048] The graphene is on the hexagonal boron nitride, and the thickness of the graphene is 0.335 nm;

[0049] The PbSe quantum dots are on the graphene, and the thickness of the PbSe quantum dots is 200 nm;

[0050] The top-gate metal electrode is on the PbSe quantum dots, and the thickness of the top-gate metal electrode is 35 nm.

[0051] As Figure 4 The performance comparison chart of the detector of the application and a conventional device shows that the response sensitivity of the application is higher than that of an ordinary light point detector and a photodiode.

[0052] Figure 5 The response wavelength and response degree relationship chart of the detector of the application shows that the application has two wave peaks, and the response wavelength range is wide.

[0053] Bias voltage is applied to the source metal electrode and the drain metal electrode of the device, so that the heterojunction is in a reverse bias state, and bias voltage is applied to the top gate, so that the two PN junctions in the vertical direction are in a reverse bias state; target light is incident to the PN junction composed of graphene and quantum dots at the top end, and the built-in electric field in the top end PN junction drives one kind of carrier to be enriched in the graphene, thereby affecting the carrier distribution of the junction region of the bottom end PN junction through the high-k value hexagonal boron nitride, and a MOSFET structure driven by light is formed; the narrow band gap characteristic and the strong light absorption capacity of the PbSe quantum dots enable the photodetector to have high sensitivity detection capacity in the short wave range; the built-in electric field formed by the bottom end PN junction enables the photogenerated carrier to be separated and an intrinsic response to be generated; the PbSe nanowire one-dimensional material can detect the middle wave infrared polarized light due to the narrow band gap characteristic and the anisotropic structure; the one-dimensional material cross section has a small effective electrical area, and in combination with the PN junction channel working in a reverse bias, the dark current can be effectively inhibited; meanwhile, the built-in electric field intensity of the two PN junctions can be controlled through the top gate, so that the device works in the amplification area of the MOSFET, and the light response is linearly amplified. The application combines the mixed dimension photovoltaic effect and the amplification mechanism of the MOSFET, and realizes a polarized, wide waveband, high sensitivity and high speed detector.

Claims

1. A hybrid-dimensionally material based composite MOSFET photodetector, characterized in that, The structure of the photoelectric detector comprises a silicon dioxide substrate, a source metal electrode, a drain metal electrode, a MoSe2 two-dimensional material, a PbSe nanowire one-dimensional material, hexagonal boron nitride, graphene, PbSe quantum dots, and a top gate metal electrode. The source metal electrode and the drain metal electrode are arranged on the upper surface of the silicon dioxide substrate, a first layer of MoSe2 two-dimensional material is arranged between the source metal electrode and the drain metal electrode, the first layer of MoSe2 two-dimensional material is not in contact with the source metal electrode and the drain metal electrode, and hollow isolation is adopted; a second layer of MoSe2 two-dimensional material is arranged on the upper surface of the source metal electrode and extends inward to be connected with the first layer of MoSe2 two-dimensional material, forming a stepped shape; the first layer of MoSe2 two-dimensional material and the upper surface of the drain metal electrode are provided with a PbSe nanowire one-dimensional material, the PbSe nanowire one-dimensional material is in a strip shape and is arranged at intervals; the PbSe nanowire one-dimensional material is sequentially stacked in the order of hexagonal boron nitride, graphene, PbSe quantum dots, and a top gate metal electrode corresponding to the upper surface of the first layer of MoSe2 two-dimensional material.

2. A hybrid-dimensionally material based composite MOSFET photodetector as claimed in claim 1, wherein, The source metal electrode, the drain metal electrode, and the top gate metal electrode are made of the same material and have a thickness of 35-45 nm.

3. A hybrid-dimensionally material based composite MOSFET photodetector as claimed in claim 1, wherein, Each layer of MoSe2 two-dimensional material has a thickness of 10-20 nm.

4. A hybrid-dimensionally material based composite MOSFET photodetector as claimed in claim 1, wherein, The PbSe nanowire one-dimensional material has a thickness of 20-30 nm, a width of 20-30 nm, and a length of 40-50 microns.

5. A hybrid-dimensionally material based composite MOSFET photodetector as claimed in claim 1, wherein, The hexagonal boron nitride has a thickness of 20-30 nm.

6. A hybrid-dimension material based composite MOSFET photodetector as claimed in claim 1, wherein, The graphene has a thickness of 0.335 nm.

7. A hybrid-dimensionally material based composite MOSFET photodetector as claimed in claim 1, wherein, The PbSe quantum dots have a thickness of 200-250 nm.

Images