A short-wave infrared photodetector and its fabrication method

Abstract

This invention discloses a short-wave infrared photodetector and its fabrication method. The detector includes a back electrode, a substrate, a barrier modification layer, a photosensitive layer, and a front electrode arranged sequentially from bottom to top. The substrate is made of Si, the barrier modification layer is made of Au, and the photosensitive layer is made of Ni. The Au barrier modification layer is used to increase the Schottky junction barrier height between Ni and Si, preventing electrons from diffusing towards the substrate in the dark state, thereby reducing the dark current. This allows the device to reduce the dark current density to less than 5 nA / cm² at an operating voltage of 0 V. 2 Dark-state noise spectral intensity is less than 10 ‑14 A / Hz 1 / 2 At a wavelength of 1550 nm and a light intensity density of 166 mW / cm², 2 Under illumination, the detector's detectivity can reach 10. 11 With a Jones-level or higher responsivity (greater than 1 mA / W) and a switching time (less than 35 μs), it possesses significant practical value. The detector features a simple stacked structure, is easy to manufacture, is compatible with CMOS semiconductor processes, has low equipment requirements, low production costs, and is easy to promote and apply.

Description

Technical Field

[0001] This invention relates to the field of photoelectric detector technology, and specifically to a short-wave infrared photoelectric detector and its fabrication method. Background Technology

[0002] Short-wave infrared photodetectors can convert optical signals with wavelengths of 1–3 μm into electrical signals and have been widely used in important fields such as military, communications, industry, medical, and security monitoring. However, currently commercially available short-wave infrared photodetectors are mainly based on narrowband semiconductor materials such as III–V group semiconductors, including InAs, GaAs, and InGaAs.

[0003] While III-V semiconductors offer certain advantages, such as adjustable bandgap, high quantum efficiency, and high carrier mobility, short-wave infrared detectors based on these materials typically require additional cooling devices to suppress dark current, resulting in larger device sizes. Furthermore, the incompatibility of III-V with CMOS semiconductor processes leads to high manufacturing costs. These issues limit their further applications.

[0004] In recent years, metal-silicon Schottky junction short-wave infrared detectors have attracted widespread attention from academia and industry. These detectors utilize a Schottky junction formed by metal and silicon to achieve photoelectric conversion, offering significant advantages such as simple fabrication, compatibility with CMOS processes, and low cost. However, these detectors suffer from relatively high dark current and low responsivity, resulting in lower performance and hindering their practical application. Summary of the Invention

[0005] Therefore, it is necessary to provide a short-wave infrared photodetector and its fabrication method to address the problems of large dark current and low responsivity in existing metal-silicon short-wave infrared detectors.

[0006] A short-wave infrared photodetector includes a back electrode, a substrate, a barrier modification layer, a photosensitive layer, and a front electrode arranged sequentially from bottom to top.

[0007] The substrate is made of Si, the barrier modification layer is made of Au, and the photosensitive layer is made of Ni. The barrier modification layer is used to increase the Schottky junction barrier height between Ni and Si, preventing electrons from the detector in the dark state from diffusing toward the substrate, thereby reducing its dark current.

[0008] In one embodiment, the thickness of the barrier modification layer is 4-8 nm.

[0009] In one embodiment, the substrate Si is N-type doped with a crystal orientation of

[100] and a resistivity of 1-10 Ω·cm.

[0010] In one embodiment, the total thickness of the substrate is 5-500 μm.

[0011] In one embodiment, the thickness of the photosensitive layer is 3-10 nm.

[0012] In one embodiment, the material of the back electrode is Al.

[0013] In one embodiment, the material of the front electrode is Au or Al.

[0014] In one embodiment, the thickness of the back electrode is 20-300 nm; and / or

[0015] The thickness of the front electrode is 20-300 nm.

[0016] A method for fabricating a shortwave infrared photodetector includes the following steps:

[0017] Clean and dry the substrate to remove surface impurities and contaminants;

[0018] An Au thin film is deposited on the substrate to form a barrier modification layer, and then a Ni thin film is deposited on the barrier modification layer to form a photosensitive layer;

[0019] A metal material is deposited on the photosensitive layer to form a front electrode, and a metal material is deposited on the back side of the substrate to form a back electrode.

[0020] In one embodiment, the barrier modification layer, the photosensitive layer, the back electrode, and the front electrode are all formed by magnetron sputtering.

[0021] The aforementioned short-wave infrared photodetector and its fabrication method have at least the following advantages:

[0022] (1) Ni is used as the photosensitive layer. Compared with other metals prepared by magnetron sputtering, Ni has a longer carrier free path and higher responsivity.

[0023] (2) The barrier modification layer can increase the Schottky junction barrier height between Ni and Si, preventing electrons from diffusing towards the substrate in the dark state. When these electrons move towards the substrate, they must overcome a higher barrier height to enter Si, which requires a higher energy threshold and a higher voltage requirement. This reduces leakage current in the device at low or no voltage, allowing the dark current density of the device to be reduced to less than 5 nA / cm at an operating voltage of 0V. 2 Dark-state noise spectral intensity is less than 10 -14 A / Hz 1 / 2 At a wavelength of 1550 nm and a light intensity density of 166 mW / cm²,2 Under illumination, the detector's detectivity can reach 10. 11 It surpasses Jones and has three orders of magnitude higher performance than conventional metal-silicon detectors, with a responsivity greater than 1 mA / W and a switching time of less than 35 μs.

[0024] (3) Short-wave infrared photodetectors with low dark current have a simple stacked structure, simple process, compatible with CMOS semiconductor process, low equipment requirements, low production cost, and are easy to promote and apply.

[0025] (4) The innovative use of Au to suppress the dark current of Ni / Si short-wave infrared photodetectors provides a new approach for the development of such devices. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0027] Figure 1 This is a schematic diagram of the structure of a short-wave infrared photodetector in one embodiment;

[0028] Figure 2 for Figure 1 The energy band structure diagram of the shortwave infrared photodetector is shown below.

[0029] Figure 3 This is a flowchart of a method for fabricating a shortwave infrared photodetector in one embodiment;

[0030] Figure 4 The dark state IT curves of Example 1 and Comparative Example 1 are shown.

[0031] Figure 5 The dark-state noise spectrum intensity curves of Example 1 and Comparative Example 1 are shown.

[0032] Figure 6 This is a switching time curve for Example 1;

[0033] Figure 7 The dark state IV curves of Examples 1, 2, 3 and Comparative Example 1 are shown.

[0034] Figure 8 The dark state IV curves are for Examples 1, 4, 5 and Comparative Example 1.

[0035] Figure 9 The graphs show the response rate versus detection rate for Examples 1, 4, and 5.

[0036] Figure label:

[0037] 10 - Back electrode, 20 - Substrate, 30 - Barrier modification layer, 40 - Photosensitive layer, 50 - Front electrode. Detailed Implementation

[0038] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention; therefore, the invention is not limited to the specific embodiments disclosed below.

[0039] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0041] Short-wave infrared photodetectors can convert optical signals with wavelengths of 1–3 μm into electrical signals and have been widely used in important fields such as military, communications, industry, medical, and security monitoring. However, currently commercially available short-wave infrared photodetectors are mainly based on narrowband semiconductor materials such as III–V group semiconductors, including InAs, GaAs, and InGaAs.

[0042] While III-V semiconductor materials offer certain advantages, such as adjustable bandgap, high quantum efficiency, and high carrier mobility, short-wave infrared detectors based on these materials typically require additional cooling devices to suppress dark currents. This results in larger device sizes, and incompatibility with CMOS semiconductor processes leads to higher fabrication costs, limiting their further applications.

[0043] Ni can generate a large number of hot electrons under short-wave infrared irradiation and possesses excellent chemical stability, which gives short-wave infrared detectors integrated from Ni and Si outstanding detection capabilities. Furthermore, these devices can be fabricated using magnetron sputtering, facilitating commercial mass production. Dark current is a crucial parameter for detector performance; a larger dark current increases the dark-state noise power and reduces the detectivity. Ni / Si short-wave infrared detectors, due to the relatively low Schottky barrier between Ni and Si, exhibit a large dark current (greater than 100 nA / cm²). 2 This cannot meet the performance requirements of today's shortwave infrared photodetectors, thus limiting their application range, which is an urgent problem to be solved.

[0044] To increase the Schottky barrier height of a Ni / Si short-wave infrared detector, Schottky barrier engineering can be used to introduce a modifying material between Ni and Si. This invention innovatively uses Au as the barrier modification layer for the Ni / Si short-wave infrared detector, enabling the device to reduce the dark current density to less than 5 nA / cm² at an operating voltage of 0 V. 2 Dark-state noise spectral intensity is less than 10 -14 A / Hz 1 / 2 Meanwhile, at a wavelength of 1550 nm and a light intensity density of 166 mW / cm², 2 Under illumination, the detector's detectivity can reach 10. 11 It surpasses Jones and has three orders of magnitude higher performance than conventional metal-silicon detectors, with a responsivity greater than 1 mA / W and a switching time of less than 35 μs.

[0045] To better understand the technical solution and beneficial effects of this application, the following detailed description is provided in conjunction with specific embodiments:

[0046] Please see Figure 1 One embodiment of the short-wave infrared photodetector includes a back electrode 10, a substrate 20, a barrier modification layer 30, a photosensitive layer 40, and a front electrode 50 arranged sequentially from bottom to top.

[0047] The substrate 20 is made of Si. In one embodiment, the substrate 20 is N-type doped, has a crystal orientation of

[100] , and a resistivity of 1-10 Ω·cm. The thickness of the substrate 20 is 5-500 μm.

[0048] The barrier modification layer 30 is made of Au. In one embodiment, the thickness of the barrier modification layer 30 is 4–8 nm. Further, the thickness of the barrier modification layer 30 is 6 nm. The barrier modification layer 30 can be prepared by magnetron sputtering. Of course, in other embodiments, the barrier modification layer 30 can also be prepared by other methods.

[0049] The photosensitive layer 40 is made of Ni. For example... Figure 2 As shown, the barrier modification layer 30 is used to increase the Schottky junction barrier height between Ni and Si, preventing electrons from diffusing towards the substrate 20 in the dark state. When these electrons move towards the substrate 20, they must overcome a higher barrier height to enter Si, which requires a higher energy threshold and a higher voltage requirement. This reduces leakage current in the device at low or no voltage, allowing the dark current density of the device to be reduced to less than 5 nA / cm² at an operating voltage of 0 V. 2 .

[0050] In one embodiment, the thickness of the photosensitive layer 40 is 3-10 nm. Specifically, the thickness of the photosensitive layer 40 is chosen to be 5 nm. The photosensitive layer 40 can be prepared by magnetron sputtering. Of course, in other embodiments, the photosensitive layer 40 can also be prepared by other methods.

[0051] In one embodiment, the back electrode 10 is made of Al, and the front electrode 50 is made of Au or Al. It is understood that the back electrode 10 and the front electrode 50 can also be made of other metallic materials, as long as they are conductive. For example, they can be Al, Ni, Ti, W, etc.

[0052] In one embodiment, the thickness of the back electrode 10 is 20-300 nm, and the thickness of the front electrode 50 is 20-300 nm. Both the back electrode 10 and the front electrode 50 can be fabricated by magnetron sputtering. Of course, the back electrode 10 and the front electrode 50 can also be fabricated by other methods; the fabrication methods can be the same or different.

[0053] Please see Figure 3 The present invention also provides a method for fabricating a short-wave infrared photodetector, used to fabricate the aforementioned short-wave infrared photodetector. Specifically, the fabrication method includes the following steps:

[0054] Step S110: Clean and dry the substrate 20 to remove surface impurities and contaminants.

[0055] Specifically, the substrate 20 is ultrasonically cleaned with acetone, ethanol and deionized water for ten minutes each, and then dried with a nitrogen gun to remove surface impurities and contaminants, thus obtaining a clean substrate 20.

[0056] Step S120: An Au thin film is deposited on the substrate 20 to form a barrier modification layer 30, and then a Ni thin film is deposited on the barrier modification layer 30 to form a photosensitive layer 40.

[0057] Specifically, a barrier modification layer 30 is formed by depositing an Au thin film using magnetron sputtering. The thickness of the Au thin film is 4–8 nm, and the vacuum degree of the magnetron sputtering method is 1 × 10⁻⁶.-5 Pa. Similarly, a photosensitive layer 40 is formed by depositing a Ni thin film using magnetron sputtering. The thickness of the Ni thin film is 3-10 nm, and the vacuum degree of the magnetron sputtering method is 1×10⁻⁶. -5 Pa.

[0058] Step S130: Deposit metal on the photosensitive layer 40 to form a front electrode 50, and deposit metal material on the back side of the substrate 20 to form a back electrode 10.

[0059] Specifically, a front electrode 50 is formed by depositing a metal material on the photosensitive layer 40 using magnetron sputtering. The metal material can be Au or Al, and the thickness of the front electrode 50 is 20-300 nm. The vacuum degree of the magnetron sputtering method is 1 × 10⁻⁶. -5 Pa.

[0060] On the back side of the substrate 20, i.e., the surface of the substrate 20 away from the barrier modification layer 30, a metal material is deposited using magnetron sputtering to form a back electrode 10. Specifically, the metal material can be Al. The thickness of the back electrode 10 is 20-300 nm, and the vacuum degree of the magnetron sputtering method is 1 × 10⁻⁶. -5 Pa.

[0061] The aforementioned short-wave infrared photodetector and its fabrication method utilize a barrier modification layer 30 to increase the Schottky junction barrier height between Ni and Si, preventing electrons from diffusing towards the substrate 20 in the dark state, thereby reducing its dark current. The short-wave infrared photodetector features a simple stacked structure, simple fabrication process, low equipment requirements, low production cost, and ease of widespread application. Using Au to suppress the dark current of Ni / Si short-wave infrared photodetectors provides a new approach for the development of this type of device.

[0062] Comparative Example 1

[0063] A short-wave infrared photodetector without barrier-free modification layer 30 was fabricated:

[0064] Step 1: Clean the substrate 20 with acetone, ethanol and deionized water in sequence using ultrasonic cleaning for 10 minutes each, and then dry it with a nitrogen gun to remove impurities and contaminants from the surface and obtain a clean substrate 20.

[0065] Step 2: Deposit a 5 nm thick Ni thin film using magnetron sputtering to form the photosensitive layer 40, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0066] Step 3: Deposit a 100 nm thick Au layer as the front electrode 50 on the front side of the device using magnetron sputtering, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0067] Step 4: Deposit a 300 nm thick Al layer as the back electrode 10 on the back side of the device using magnetron sputtering, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0068] Example 1

[0069] A method for fabricating a shortwave infrared photodetector includes the following steps:

[0070] Step 1: Clean the substrate 20 with acetone, ethanol and deionized water in sequence using ultrasonic cleaning for 10 minutes each, and then dry it with a nitrogen gun to remove impurities and contaminants from the surface and obtain a clean substrate 20.

[0071] Step 2: Deposit a 6 nm thick Au thin film using magnetron sputtering to form a barrier modification layer 30, with a vacuum degree of 1 × 10⁻⁶. -5 Pa.

[0072] Step 3: Deposit a 5 nm thick Ni thin film using magnetron sputtering to form the photosensitive layer 40, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0073] Step 4: Deposit a 100 nm thick Au layer on the front side of the device as the back electrode 10 using magnetron sputtering, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0074] Step 5: Deposit a 300 nm thick Al layer on the back side of the device as the front electrode 50 using magnetron sputtering, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0075] Example 2

[0076] A method for fabricating a shortwave infrared photodetector includes the following steps:

[0077] Step 1: Clean the substrate 20 with acetone, ethanol and deionized water in sequence using ultrasonic cleaning for 10 minutes each, and then dry it with a nitrogen gun to remove impurities and contaminants from the surface and obtain a clean substrate 20.

[0078] Step 2: Deposit a 6 nm thick Ag film using magnetron sputtering to form a barrier modification layer 30, with a vacuum degree of 1 × 10⁻⁶. -5 Pa.

[0079] Step 3: Deposit a 5 nm thick Ni thin film using magnetron sputtering to form the photosensitive layer 40, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0080] Step 4: Deposit a 100 nm thick Au layer as the front electrode 50 on the front side of the device using magnetron sputtering, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0081] Step 5: Deposit a 300 nm thick Al layer as the back electrode 10 on the back side of the device using magnetron sputtering, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0082] Example 3

[0083] A method for fabricating a shortwave infrared photodetector includes the following steps:

[0084] Step 1: Clean the substrate 20 with acetone, ethanol and deionized water in sequence using ultrasonic cleaning for 10 minutes each, and then dry it with a nitrogen gun to remove impurities and contaminants from the surface and obtain a clean substrate 20.

[0085] Step 2: Deposit a 6 nm thick Ti thin film using magnetron sputtering to form a barrier modification layer 30, with a vacuum degree of 1 × 10⁻⁶. -5 Pa.

[0086] Step 3: Deposit a 5 nm thick Ni thin film using magnetron sputtering to form the photosensitive layer 40, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0087] Step 4: Deposit a 100 nm thick Au layer as the front electrode 50 on the front side of the device using magnetron sputtering, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0088] Step 5: Deposit a 300 nm thick Al layer as the back electrode 10 on the back side of the device using magnetron sputtering, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0089] Example 4

[0090] A method for fabricating a shortwave infrared photodetector includes the following steps:

[0091] Step 1: Clean the substrate 20 with acetone, ethanol and deionized water in sequence using ultrasonic cleaning for 10 minutes each, and then dry it with a nitrogen gun to remove impurities and contaminants from the surface and obtain a clean substrate 20.

[0092] Step 2: Deposit a 4 nm thick Au thin film using magnetron sputtering to form a barrier layer at a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0093] Step 3: Deposit a 5 nm thick Ni thin film using magnetron sputtering to form the photosensitive layer 40, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0094] Step 4: Deposit a 100 nm thick Au layer on the front side of the device as the back electrode 10 using magnetron sputtering, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0095] Step 5: Deposit a 300 nm thick Al layer on the back side of the device as the front electrode 50 using magnetron sputtering, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0096] Example 5

[0097] A method for fabricating a shortwave infrared photodetector includes the following steps:

[0098] Step 1: Clean the substrate 20 with acetone, ethanol and deionized water in sequence using ultrasonic cleaning for 10 minutes each, and then dry it with a nitrogen gun to remove impurities and contaminants from the surface and obtain a clean substrate 20.

[0099] Step 2: Deposit an 8 nm thick Au thin film using magnetron sputtering to form a barrier modification layer 30, with a vacuum degree of 1 × 10⁻⁶. -5 Pa.

[0100] Step 3: Deposit a 5 nm thick Ni thin film using magnetron sputtering to form the photosensitive layer 40, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0101] Step 4: Deposit a 100 nm thick Au layer as the front electrode 50 on the front side of the device using magnetron sputtering, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0102] Step 5: Deposit a 300 nm thick Al layer as the back electrode 10 on the back side of the device using magnetron sputtering, with a vacuum level of 1 × 10⁻⁶. -5 Pa.

[0103] Figure 4 The figures show the dark-state IT curves for Example 1 and Comparative Example 1. The results show that Example 1 has a lower dark current density (less than 5 nA / cm²). 2 It is more suitable for use in Ni / Si short-wave infrared photodetectors.

[0104] Figure 5 The figures show the dark-state noise spectrum intensity curves for Example 1 and Comparative Example 1. The results show that Example 1 has a lower dark-state noise spectrum intensity (less than 10). -14 A / Hz 1 / 2 It is more suitable for use in Ni / Si short-wave infrared photodetectors.

[0105] Figure 6 The figure shows the switching time curve for Example 1. The results indicate that Example 1 has a fast response time (less than 35 μs), making it suitable for use in Ni / Si short-wave infrared photodetectors.

[0106] Figure 7The figures show the dark-state IV curves provided in Examples 1, 2, and 3 of this invention, and Comparative Example 1. The barrier modification layer 30 materials in Examples 1, 2, and 3 are Au, Ag, and Ti, respectively, with a thickness of 6 nm. The results show that Au significantly outperforms the other two materials in suppressing the 0V dark current density of the device, making it more suitable for use in Ni / Si short-wave infrared photodetectors.

[0107] Figure 8 The figures show the dark-state IV curves provided in Embodiments 1, 4, and 5 of this invention and Comparative Example 1. The thicknesses of the barrier modification layer 30 in Embodiments 1, 4, and 5 are 6 nm, 4 nm, and 8 nm, respectively. The results show that the 6 nm thick device exhibits a lower dark current density at 0 V, making it more suitable for use in Ni / Si short-wave infrared photodetectors.

[0108] Figure 9 The graphs show the responsivity and detectivity curves for Examples 1, 4, and 5. The thicknesses of the barrier modification layer 30 in Examples 1, 4, and 5 are 6 nm, 4 nm, and 8 nm, respectively. The results show that the 6 nm thick device exhibits higher responsivity (greater than 1 mA / W) and detectivity (greater than 10). 11 Jones) is more suitable for use in Ni / Si short-wave infrared photodetectors.

[0109] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A short-wave infrared photodetector, characterized in that, It includes, from bottom to top, a back electrode, a substrate, a barrier modification layer, a photosensitive layer, and a front electrode; The substrate is made of Si, the barrier modification layer is made of Au, and the photosensitive layer is made of Ni. The barrier modification layer is used to increase the Schottky junction barrier height between Ni and Si, preventing electrons from the detector in the dark state from diffusing toward the substrate, thereby reducing its dark current.

2. The shortwave infrared photodetector according to claim 1, characterized in that, The thickness of the barrier modification layer is 4-8 nm.

3. The shortwave infrared photodetector according to claim 1, characterized in that, The substrate Si is N-type doped with a crystal orientation of [100] and a resistivity of 1-10 Ω·cm.

4. The shortwave infrared photodetector according to claim 3, characterized in that, The total thickness of the substrate is 5-500 μm.

5. The shortwave infrared photodetector according to claim 1, characterized in that, The thickness of the photosensitive layer is 3-10 nm.

6. The shortwave infrared photodetector according to claim 1, characterized in that, The material of the back electrode is Al.

7. The shortwave infrared photodetector according to claim 1, characterized in that, The material of the front electrode is Au or Al.

8. The shortwave infrared photodetector according to claim 1, characterized in that, The thickness of the back electrode is 20-300 nm; and / or The thickness of the front electrode is 20-300 nm.

9. A method for fabricating a shortwave infrared photodetector, characterized in that, Includes the following steps: Clean and dry the substrate to remove surface impurities and contaminants; An Au thin film is deposited on the substrate to form a barrier modification layer, and then a Ni thin film is deposited on the barrier modification layer to form a photosensitive layer; A metal material is deposited on the photosensitive layer to form a front electrode, and a metal material is deposited on the back side of the substrate to form a back electrode.

10. The method for fabricating a shortwave infrared photodetector according to claim 9, characterized in that, The barrier modification layer, the photosensitive layer, the back electrode, and the front electrode are all formed by magnetron sputtering.

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