Application of palladium telluride gallium nitride Schottky heterojunction in polarized ultraviolet light detection and polarized ultraviolet photoelectric detector
By using palladium-telluride gallium nitride Schottky heterojunction in polarization photodetectors, the complexity of short-wave ultraviolet band detection and two-dimensional layered materials are solved in the prior art by using the anisotropic characteristics of palladium-telluride materials. The problem of application limitations has achieved efficient polarization ultraviolet light detection and structural simplification.
Patent Information
- Application Number
- CN202411523982.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-30
- Publication Date
- 2025-02-07
AI Technical Summary
The complex processes and increased complexity of existing polarized photodetectors in the short-wave UV frequency band limit their application, and the application of two-dimensional layered materials in UV photoelectronics is limited.
Using palladium telluride gallium nitride Schottky heterojunction, the electrical and optical anisotropy of palladium telluride material can be used to achieve anisotropic light absorption of polarized ultraviolet light by forming a Schottky heterojunction structure, thereby performing Effective polarization ultraviolet light detection.
It realizes efficient detection of polarized ultraviolet light, simplifies the detector structure, improves the response speed, and expands its application potential in the short-wave ultraviolet frequency band.
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Figure CN119403248A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an application of a palladium telluride gallium nitride Schottky heterojunction in polarized ultraviolet light detection and a polarized ultraviolet photoelectric detector, belonging to the technical field of semiconductor optoelectronic devices. Background Art
[0002] Polarization characteristics, as one of the basic properties of light, play a vital role in the fields of photonics and electronics. Polarization-sensitive photodetectors will produce anisotropic light responses to polarized light at different angles, so polarization-sensitive photodetectors can be widely used in target detection, deep space exploration, environmental monitoring and other fields. In order to achieve polarization photodetection, common methods include utilizing the intrinsic anisotropic light response of materials to polarized light, or utilizing anisotropic mechanisms in morphology, such as by introducing periodic subwavelength metal or dielectric grating structures as polarization-sensitive optical components. However, the introduction of additional polarization-sensitive optical components will increase the complexity of polarization detection devices or systems. In addition, in the short-wave ultraviolet operating frequency band, the manufacturing process of subwavelength metal or dielectric grating structures is relatively complicated.
[0003] Two-dimensional layered semiconductor materials have become promising candidates for polarized light detection due to their intrinsic anisotropy caused by asymmetric crystal structures. However, due to the small band gap, the application of two-dimensional layered materials in optoelectronics is mainly limited to the infrared region. III-V nitride semiconductors are essential for ultraviolet photodetection. Therefore, the combination of two-dimensional layered materials and III-V nitrides will open up new avenues for short-wave ultraviolet polarized optoelectronics. Palladium telluride, as a new type of Dirac semimetal material, has optoelectronic properties such as high carrier mobility, good air stability, and wide spectrum absorption. In a single layer of palladium telluride, one palladium atom is covalently bonded to the surrounding six tellurium atoms. In multilayer palladium telluride, the layers are stacked by weak van der Waals interactions. As the number of grown layers increases, the properties of palladium telluride change from semiconductor to semimetal. Its band structure is a highly tilted Dirac cone, which can achieve rapid separation and transfer of carriers. This unique band structure also leads to the unique electrical anisotropy and optical anisotropy properties of the material itself, giving it broad prospects in polarized light sensitive detection. Summary of the invention
[0004] The invention discloses an application of a palladium telluride gallium nitride Schottky heterojunction in polarized ultraviolet light detection. The palladium telluride gallium nitride Schottky heterojunction comprises a gallium nitride layer and a palladium telluride layer, wherein the gallium nitride layer and the palladium telluride layer form a Schottky heterojunction structure, and the electrical and optical anisotropy of the palladium telluride material itself is utilized to realize anisotropic light absorption of polarized ultraviolet light by the palladium telluride gallium nitride Schottky heterojunction, thereby performing effective polarized ultraviolet light detection.
[0005] Preferably, an isolation layer is further included, wherein the isolation layer is grown on one side of the surface of the gallium nitride layer, and one end of the palladium telluride layer is located on the surface of the isolation layer, and the other end is located on the surface of the gallium nitride layer.
[0006] Preferably, the gallium nitride layer has a thickness of 2-4 μm, and the palladium telluride layer has a thickness of 30-200 nm.
[0007] Preferably, the isolation layer material is SiO2 or Si3N4, and has a thickness of 20-50 nm.
[0008] The present invention also discloses a polarized ultraviolet photodetector based on a palladium telluride gallium nitride Schottky heterojunction, the structure of which includes:
[0009] a substrate;
[0010] A palladium telluride gallium nitride Schottky heterojunction, wherein the palladium telluride gallium nitride Schottky heterojunction comprises a gallium nitride layer and a palladium telluride layer, wherein the gallium nitride layer and the palladium telluride layer form a Schottky heterojunction structure, wherein the gallium nitride layer is grown on a substrate;
[0011] A Ni / Au electrode and a Ti / Al / Ni / Au electrode, wherein the Ni / Au electrode is grown on the PdTe layer and the Ti / Al / Ni / Au electrode is grown on the GaN layer.
[0012] Preferably, it also includes an isolation layer, which is grown on one side of the surface of the gallium nitride layer, one end of the palladium telluride layer is located on the surface of the isolation layer, and the other end is located on the surface of the gallium nitride layer, and the Ni / Au electrode is grown on the palladium telluride layer above the isolation layer portion.
[0013] Preferably, the substrate layer is a sapphire substrate with a thickness of 200-500 μm.
[0014] Preferably, the width of the Ni / Au electrode is 20-150μm, the length is 20-150μm, the Ni metal thickness is 20-50nm, and the Au metal thickness is 50-200nm; the width of the Ti / Al / Ni / Au electrode is 20-100μm, the length is 100-200μm, wherein the Ti metal thickness is 20-50nm, the Al metal thickness is 100-120nm, the Ni metal thickness is 40-60nm, and the Au metal thickness is 70-120nm.
[0015] Preferably, the gallium nitride layer has a thickness of 2-4 μm, the palladium telluride layer has a thickness of 30-200 nm, and the palladium telluride layer is epitaxially grown directly on the gallium nitride layer by metal post-sulfurization.
[0016] Preferably, the isolation layer material is SiO2 or Si3N4, and has a thickness of 20-50 nm.
[0017] The present invention also discloses a method for preparing the polarized ultraviolet photoelectric detector, which is characterized in that the method comprises the following steps:
[0018] (1) Sample pretreatment: clean the surface of the GaN sample and remove organic impurities on the surface;
[0019] (2) Preparation of isolation layer: growing the isolation layer by plasma deposition technology, defining the isolation layer mask by photolithography technology, and obtaining the desired isolation layer pattern by dry etching;
[0020] (3) Preparation of Ti / Al / Ni / Au electrodes: Use photolithography technology to make an electrode mask, use electron beam evaporation technology to deposit an ohmic contact electrode on the gallium nitride side, and after peeling off, obtain a metal electrode with the target pattern, and form an ohmic contact through high-temperature annealing;
[0021] (4) Epitaxial growth of palladium telluride layer: a palladium telluride layer is grown on the surface of the isolation layer and above the gallium nitride layer by a metal post-sulfurization method;
[0022] (5) Preparation of Ni / Au electrode: The electrode mask is made using photolithography technology, and metal is deposited on the palladium telluride layer using electron beam evaporation. The target metal electrode is obtained after peeling.
[0023] Preferably, the metal post-sulfurization method refers to first making a Pd metal mask pattern on the surface of the isolation layer and the area above the gallium nitride layer by photolithography technology, and then using electron beam evaporation to deposit a Pd metal film with a Pd thickness of 2-20nm. In a double-temperature zone tubular furnace, tellurium powder is placed in an upstream quartz boat, and an experimental sample is placed in a downstream quartz boat, and a palladium telluride layer is epitaxially grown by chemical vapor deposition.
[0024] The present invention proposes a polarized ultraviolet photodetector based on a palladium telluride gallium nitride Schottky heterojunction, which utilizes the electrical and optical anisotropy of the palladium telluride material itself to realize the anisotropic light absorption of polarized ultraviolet light by the palladium telluride gallium nitride Schottky heterojunction, thereby effectively detecting polarized ultraviolet light. In addition, after the palladium telluride layer is directly epitaxially grown on the gallium nitride layer by the method of metal post-sulfurization, a high-quality Schottky heterojunction is formed, and the photogenerated carriers can be quickly separated and transferred to the electrodes at both ends after being generated, thereby accelerating the response speed of the detector. The detector has a simple structure and has high-quality Schottky junction characteristics, which is conducive to further promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 A device structure diagram of a polarized ultraviolet photodetector based on a palladium telluride-gallium nitride Schottky heterojunction provided by the present invention.
[0026] Figure 2A top view of a polarized ultraviolet photodetector based on a palladium telluride-gallium nitride Schottky heterojunction provided by the present invention.
[0027] Figure 3 This is a polar coordinate diagram of the photocurrent of the polarized ultraviolet photodetector based on palladium telluride gallium nitride Schottky heterojunction in Example 1 as a function of the incident polarized light angle.
[0028] Figure 4 This is a polar coordinate diagram of the photocurrent of the polarized ultraviolet photodetector based on palladium telluride gallium nitride Schottky heterojunction in Example 2 as a function of the incident polarized light angle.
[0029] Figure 5 This is a device structure diagram of the polarized ultraviolet photodetector based on palladium telluride gallium nitride Schottky heterojunction in Example 3.
[0030] Markings in the figure: 1-sapphire substrate layer, 2-gallium nitride layer, 3-isolation layer, 4-palladium telluride layer, 5-Ni / Au electrode layer, 6-Ti / Al / Ni / Au electrode layer. DETAILED DESCRIPTION
[0031] The present invention is further described below in conjunction with embodiments, but the description of the embodiments does not impose any limitation on the protection scope of the present invention.
[0032] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the technical field of the present invention, and the terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. In addition, although a demonstration of parameters containing specific values may be provided herein, it should be understood that the parameters do not need to be exactly equal to the corresponding values, but can be approximated to the corresponding values within an acceptable error tolerance or design constraint. The directional terms mentioned in the embodiments, such as "up", "down", "front", "back", "left", "right", etc., are only with reference to the directions of the accompanying drawings. Therefore, the directional terms used are used to illustrate rather than to limit the scope of protection of the present invention.
[0033] Unless otherwise specified, the materials and instruments used in the following examples can be obtained from conventional commercial channels.
[0034] Example 1
[0035] This embodiment provides a polarized ultraviolet photodetector based on a palladium telluride gallium nitride Schottky heterojunction, comprising a substrate layer, a palladium telluride gallium nitride Schottky heterojunction active layer on the substrate layer, an isolation layer, a Ti / Al / Ni / Au electrode layer, and a Ni / Au electrode layer. The palladium telluride layer is directly epitaxially grown on the gallium nitride layer by metal post-sulfurization, and the gallium nitride layer is covered with a Ti / Al / Ni / Au contact electrode on one side, and the palladium telluride layer is covered with a Ni / Au contact electrode on one side. The process flow specifically includes the following steps:
[0036] (1) Cleaning of GaN samples: The GaN samples epitaxially grown on sapphire substrates were placed in an acetone solution and ultrasonically cleaned for 10 min to remove organic impurities on the sample surface. The samples were then placed in an ethanol solution and cleaned for 10 min. They were then ultrasonically cleaned in deionized water for 10 min, and the surface of the GaN samples were dried with high-purity nitrogen.
[0037] (2) Preparation of isolation layer: First, a uniform silicon oxide film is prepared on the surface of the gallium nitride sample using plasma enhanced chemical vapor deposition technology. The gas flow rates of SiH4 / N2 and N2O are set to 100sccm and 400sccm respectively, the gas pressure during the reaction is set to 300mTorr, the power is set to 10W, and the growth time is 2min. Then, a photoresist mask is prepared on the silicon oxide surface by photolithography technology, and the silicon oxide film in the isolation layer area is retained by dry etching. In the dry etching, the CF4 gas flow rate is set to 30sccm, the plasma bombardment power is set to 120W, the ambient pressure is set to 4Pa, and the etching time is 1min 30s. The function of the isolation layer is to prevent the Ni / Au electrode from directly contacting the gallium nitride film when the palladium telluride is thinner. Therefore, it can be the same size as the Ni / Au electrode or slightly larger than the Ni / Au electrode.
[0038] (3) Preparation of Ti / Al / Ni / Au electrodes: The photoresist mask required for evaporation of Ti / Al / Ni / Au electrodes was prepared by photolithography, and then Ti / Al / Ni / Au stacked metals were deposited by electron beam evaporation with thicknesses of 20 / 120 / 50 / 100 nm, respectively. The metal electrodes were obtained after peeling. The samples with metal electrodes were placed in a rapid annealing furnace and maintained at 850°C for 30 seconds to form ohmic contacts.
[0039] (4) Epitaxial growth of palladium telluride layer: First, a 10nm Pd metal film is deposited on the surface of the isolation layer and the area above the gallium nitride by combining photolithography technology with electron beam evaporation technology, where the evaporation rate is set to 0.01nm / s. Then, the gallium nitride sample with the Pd metal film is placed in a quartz boat downstream of the dual-temperature zone tube furnace, and 0.5mg of tellurium powder is placed in the upstream quartz boat. Argon is used as the carrier gas, and the flow rate is set to 500sccm. The palladium telluride layer is grown by heating at 450°C for one hour. The thickness of the palladium telluride layer is distributed in the range of 50-80nm.
[0040] (5) Preparation of Ni / Au electrodes: The required photoresist pattern is prepared on the palladium telluride layer by photolithography technology, and Ni / Au metal electrodes are deposited on the palladium telluride layer by electron beam evaporation with a thickness of 50 / 100 nm and an evaporation rate of 0.05 nm / s.
[0041] In Example 1, the thickness of the substrate layer and the gallium nitride layer are 460 μm and 3.5 μm, respectively. After the above process steps, a polarized ultraviolet photodetector based on palladium telluride gallium nitride Schottky heterojunction is successfully prepared. The schematic diagram of the structure of the polarized ultraviolet photodetector device based on palladium telluride gallium nitride Schottky heterojunction is shown in FIG. Figure 1 As shown, the top view is Figure 2 As shown. Figure 3 From the polar coordinate diagram of the photocurrent changing with the angle of incident polarized light, it can be found that when the bias voltage is -3V, the device has anisotropic photoresponse to 365nm ultraviolet polarized light incident at different angles, achieving high-performance ultraviolet polarized light detection.
[0042] Example 2
[0043] This embodiment provides a polarized ultraviolet photodetector based on a palladium telluride gallium nitride Schottky heterojunction, comprising a substrate layer, a palladium telluride gallium nitride Schottky heterojunction active layer on the substrate layer, an isolation layer, a Ti / Al / Ni / Au electrode layer, and a Ni / Au electrode layer. The palladium telluride layer is directly epitaxially grown on the gallium nitride layer by metal post-sulfurization, and the gallium nitride layer is covered with a Ti / Al / Ni / Au contact electrode on one side, and the palladium telluride layer is covered with a Ni / Au contact electrode on one side. The process flow specifically includes the following steps:
[0044] (1) Cleaning of GaN samples: The GaN samples epitaxially grown on sapphire substrates were placed in an acetone solution and ultrasonically cleaned for 10 min to remove organic impurities on the sample surface. The samples were then placed in an ethanol solution and cleaned for 10 min. They were then ultrasonically cleaned in deionized water for 10 min, and the surface of the GaN samples were dried with high-purity nitrogen.
[0045] (2) Preparation of isolation layer: First, a uniform silicon oxide film is prepared on the surface of the gallium nitride sample using plasma enhanced chemical vapor deposition technology. The gas flow rates of SiH4 / N2 and N2O are set to 400sccm and 500sccm respectively, the gas pressure during the reaction is set to 700mTorr, the power is set to 50W, and the growth time is 20s. Then, a photoresist mask is prepared on the silicon oxide surface by photolithography technology, and the silicon oxide film in the isolation layer area is retained by dry etching. In the dry etching, the CF4 gas flow rate is set to 30sccm, the plasma bombardment power is set to 120W, the ambient pressure is set to 4Pa, and the etching time is 1min 30s.
[0046] (3) Preparation of Ti / Al / Ni / Au electrodes: The photoresist mask required for evaporation of Ti / Al / Ni / Au electrodes was prepared by photolithography, and then Ti / Al / Ni / Au stacked metals were deposited by electron beam evaporation with thicknesses of 50 / 100 / 50 / 100 nm, respectively, and metal electrodes were obtained after peeling. The sample with metal electrodes was placed in a rapid annealing furnace and maintained at 850°C for 30 seconds to form an ohmic contact.
[0047] (4) Epitaxial growth of palladium telluride layer: First, a 10nm Pd metal film is deposited on the surface of the isolation layer and the area above the gallium nitride by combining photolithography technology with electron beam evaporation technology, where the evaporation rate is set to 0.02nm / s. Then, the gallium nitride sample with the Pd metal film is placed in a quartz boat downstream of the dual-temperature zone tube furnace, and 0.3mg of tellurium powder is placed in the upstream quartz boat. Argon is used as the carrier gas, and the flow rate is set to 200sccm. After heating at 450oC for one hour, the growth of the palladium telluride layer is completed. The thickness of the palladium telluride layer is distributed in the range of 30-50nm.
[0048] (5) Preparation of Ni / Au electrode: The required photoresist pattern is prepared on the palladium telluride layer by photolithography technology, and Ni / Au metal is deposited by electron beam evaporation technology with a thickness of 50 / 200 nm and an evaporation rate of 0.1 nm / s.
[0049] In Example 2, the thickness of the substrate layer and the gallium nitride layer are 460 μm and 3 μm, respectively. After the above process steps, a polarized ultraviolet photodetector based on palladium telluride gallium nitride Schottky heterojunction is successfully prepared. Figure 4 From the polar coordinate diagram of the photocurrent changing with the angle of incident polarized light, it can be found that when the bias voltage is -5V, the device has anisotropic photoresponse to 365nm ultraviolet polarized light incident at different angles, achieving high-performance ultraviolet polarized light detection.
[0050] Example 3
[0051] This embodiment provides a polarized ultraviolet photodetector based on a palladium telluride gallium nitride Schottky heterojunction, comprising a substrate layer, a palladium telluride gallium nitride Schottky heterojunction active layer on the substrate layer, a Ti / Al / Ni / Au electrode layer, and a Ni / Au electrode layer. The palladium telluride layer is directly epitaxially grown on the gallium nitride layer by metal post-sulfurization, and the gallium nitride layer is covered with a Ti / Al / Ni / Au contact electrode on one side, and the palladium telluride layer is covered with a Ni / Au contact electrode on one side. The process flow specifically includes the following steps:
[0052] (1) Cleaning of GaN samples: The GaN samples grown epitaxially on sapphire substrates were placed in an acetone solution and cleaned by ultrasonic method for 10 min to remove organic impurities on the sample surface. The samples were then placed in an ethanol solution and cleaned for 10 min. The samples were then placed in deionized water and cleaned by ultrasonic method for 10 min. The surface of the GaN samples was then dried with high-purity nitrogen.
[0053] (2) Preparation of Ti / Al / Ni / Au electrodes: The photoresist mask required for evaporation of Ti / Al / Ni / Au electrodes was prepared by photolithography, and then Ti / Al / Ni / Au stacked metals were deposited by electron beam evaporation with thicknesses of 50 / 100 / 50 / 100 nm, respectively, and the metal electrodes were obtained after peeling. The sample with the metal electrode was placed in a rapid annealing furnace and maintained at 850°C for 30 seconds to form an ohmic contact.
[0054] (3) Epitaxial growth of palladium telluride layer: First, a 20nm Pd metal film is deposited on the area above the gallium nitride by combining photolithography technology with electron beam evaporation technology, where the evaporation rate is set to 0.03nm / s. Then, the gallium nitride sample with the Pd metal film is placed in a quartz boat downstream of the dual-temperature zone tube furnace, and 1.0mg of tellurium powder is placed in the upstream quartz boat. Argon is used as the carrier gas, and the flow rate is set to 200sccm. After heating at 450℃ for one hour, the growth of the palladium telluride layer is completed, and the thickness is distributed in the range of 150-200nm.
[0055] (4) Preparation of Ni / Au electrode: The required photoresist pattern is prepared on the palladium telluride layer by photolithography technology, and Ni / Au metal is deposited by electron beam evaporation technology with a thickness of 50 / 200 nm and an evaporation rate of 0.2 nm / s.
[0056] In Example 3, the thickness of the substrate layer and the gallium nitride layer are 460 μm and 3 μm, respectively. After the above process steps, a polarized ultraviolet photodetector based on palladium telluride gallium nitride Schottky heterojunction is successfully prepared. The schematic diagram of the structure of the prepared polarized ultraviolet photodetector device based on palladium telluride gallium nitride Schottky heterojunction is shown in FIG. Figure 5 shown.
[0057] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principle of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention. In order to better illustrate the embodiments, some parts in the drawings will be omitted or scaled, and do not represent the actual size of the device.
Claims
1. Application of a palladium telluride gallium nitride Schottky heterojunction in polarized ultraviolet light detection, wherein the palladium telluride gallium nitride Schottky heterojunction comprises a gallium nitride layer and a palladium telluride layer, and the gallium nitride layer and the palladium telluride layer form a Schottky heterojunction structure.
2. The use according to claim 1, characterized in that: The invention also comprises an isolation layer, wherein the isolation layer is grown on one side of the surface of the gallium nitride layer, and one end of the palladium telluride layer is located on the surface of the isolation layer, and the other end is located on the surface of the gallium nitride layer.
3. The use according to claim 1 or 2, characterized in that: The gallium nitride layer has a thickness of 2-4 μm, and the palladium telluride layer has a thickness of 30-200 nm.
4. The use according to claim 3, characterized in that: The isolation layer is made of SiO2 or Si3N4 and has a thickness of 20-50nm.
5. A polarized ultraviolet photodetector based on palladium telluride gallium nitride Schottky heterojunction, characterized in that: Its structure includes: a substrate; A palladium telluride gallium nitride Schottky heterojunction, wherein the palladium telluride gallium nitride Schottky heterojunction comprises a gallium nitride layer and a palladium telluride layer, wherein the gallium nitride layer and the palladium telluride layer form a Schottky heterojunction structure, wherein the gallium nitride layer is grown on a substrate; A Ni / Au electrode and a Ti / Al / Ni / Au electrode, wherein the Ni / Au electrode is grown on the PdTe layer and the Ti / Al / Ni / Au electrode is grown on the GaN layer.
6. The polarized ultraviolet photodetector according to claim 5, characterized in that: It also includes an isolation layer, which is grown on one side of the surface of the gallium nitride layer. One end of the palladium telluride layer is located on the surface of the isolation layer, and the other end is located on the surface of the gallium nitride layer. The Ni / Au electrode is grown on the palladium telluride layer above the isolation layer.
7. The polarized ultraviolet photodetector according to claim 5 or 6, characterized in that: The substrate layer is made of sapphire substrate, silicon substrate or silicon carbide substrate, and has a thickness of 200-500 μm.
8. The polarized ultraviolet photodetector according to claim 5 or 6, characterized in that: The width of the Ni / Au electrode is 20-150μm, the length is 20-150μm, the Ni metal thickness is 20-50nm, and the Au metal thickness is 50-200nm; the width of the Ti / Al / Ni / Au electrode is 20-100μm, the length is 100-200μm, wherein the Ti metal thickness is 20-50nm, the Al metal thickness is 90-120nm, the Ni metal thickness is 40-60nm, and the Au metal thickness is 70-120nm.
9. The polarized ultraviolet photodetector according to claim 5 or 6, characterized in that: The gallium nitride layer has a thickness of 2-4 μm, the palladium telluride layer has a thickness of 30-200 nm, and the palladium telluride layer is directly epitaxially grown on the gallium nitride layer by metal post-sulfurization.
10. The polarized ultraviolet photodetector according to any one of claims 6 to 9, characterized in that: The isolation layer is made of SiO2 or Si3N4 and has a thickness of 20-50nm.