Light detector and manufacturing method thereof

Abstract

The invention discloses a light detector and a manufacturing method thereof. The light detector comprises a lower electrode layer, an absorption layer and an upper electrode layer. And the absorption layer is positioned on the lower electrode layer and comprises a material of which the electron mobility needs to be greater than 300cm < 2 > / Vs and is also greater than twice of the hole mobility. The upper electrode layer is located on the absorption layer and is configured to absorb high-speed photoelectrons scattered around the upper electrode and leave low-speed photoholes, so that positive charges are generated on the upper surface and photovoltages are generated on the absorption layer, and then downward photocurrents are generated. The absorption layer of the photodetector comprises the material with the electron mobility being two times greater than the hole mobility, so that the photocurrent can be generated by utilizing the great difference of the electron-hole mobility, and the photodetector can be independently operated at room temperature without the assistance of a cooling system and can also be operated under zero bias voltage; therefore, the infrared ray detection with high detection rate can be provided.

Description

Technical Field

[0001] The present disclosure relates to a light detector and a method for manufacturing the light detector. Background Art

[0002] In the field of mid- and far-infrared detection, infrared detectors can be divided into two types: one is a detector that can operate at room temperature, and the other is a refrigerated detector. Generally speaking, detectors that operate at room temperature have lower signal detection rates and image resolutions and cannot provide more accurate measurements. Only refrigerated detectors can provide higher detection rates and resolutions.

[0003] However, the above-mentioned uncooled detectors usually need to be cooled to the temperature of liquid nitrogen to operate normally because of the large dark current. This makes the maintenance cost of this type of detector very high, and because the cooling system is generally much larger than the detector itself, it also makes this type of detector difficult to set up. Summary of the invention

[0004] One technical aspect of the present disclosure is a light detector.

[0005] According to one embodiment of the present disclosure, a photodetector includes a lower electrode layer, an absorption layer, and an upper electrode layer. The absorption layer is located on the lower electrode layer, wherein the absorption layer includes an electron mobility greater than 300 cm 2 The absorption layer is configured to generate photocurrent by utilizing the large difference between electron mobility and hole mobility. The upper electrode layer is located on the absorption layer and configured to absorb electrons in the photocurrent.

[0006] In one embodiment of the present disclosure, the absorption layer includes a semiconductor-semiconductor junction, a semiconductor-semimetal junction, a semimetal-semimetal junction, or a combination thereof with a built-in electric field pointing downward.

[0007] In one embodiment of the present disclosure, the top-view shape of the upper electrode layer is at least one of a comb shape, a tree shape, a mesh shape, or a spiral shape.

[0008] In one embodiment of the present disclosure, the top electrode layer is located in the groove of the absorption layer.

[0009] In one embodiment of the present disclosure, the top electrode layer forms an ohmic contact or a Schottky contact with the absorption layer.

[0010] In one embodiment of the present disclosure, the light detector further includes a substrate, which is located between the absorption layer and the lower electrode layer.

[0011] In one embodiment of the present disclosure, the light detector further includes a buffer layer. The buffer layer is located between the substrate and the absorption layer.

[0012] In one embodiment of the present disclosure, the top electrode layer has a rectangular shape in a top view.

[0013] In one embodiment of the present disclosure, the material of the upper electrode layer is a transparent conductive film including indium tin oxide (ITO) or aluminum zinc oxide (AZO).

[0014] In one embodiment of the present disclosure, the light detector further includes a cover layer. The cover layer is located on the absorption layer and surrounds the upper electrode layer.

[0015] Another technical aspect of the present disclosure is a method for manufacturing a light detector.

[0016] According to one embodiment of the present disclosure, a method for manufacturing a photodetector includes providing an absorption layer, wherein the absorption layer includes an electron mobility greater than 300 cm 2 / Vs is also greater than twice its hole mobility, the absorption layer is configured to use the huge difference between electron mobility and hole mobility to generate photovoltage and thus form photocurrent; an upper electrode layer is plated on the absorption layer, wherein the upper electrode layer is configured to absorb scattered high-speed photoelectrons and destroy electrical neutrality around the upper electrode layer, causing positive charge accumulation of holes to generate photovoltage; and a lower electrode layer is formed so that the absorption layer is located between the upper electrode layer and the lower electrode layer.

[0017] In one embodiment of the present disclosure, providing the absorption layer includes forming the absorption layer on the substrate.

[0018] In one embodiment of the present disclosure, forming the lower electrode layer so that the absorption layer is located between the upper electrode layer and the lower electrode layer includes forming the lower electrode layer on a surface of the substrate facing away from the absorption layer.

[0019] In one embodiment of the present disclosure, forming the absorption layer on the substrate includes forming the absorption layer by diffusion or ion distribution.

[0020] In one embodiment of the present disclosure, forming the absorption layer on the substrate includes using at least one of molecular beam epitaxy, chemical vapor deposition, physical vapor deposition, atomic layer deposition or liquid phase epitaxy.

[0021] In one embodiment of the present disclosure, a lower electrode layer is formed on a surface of the substrate facing away from the absorption layer so that the lower electrode layer forms an ohmic contact or a Schottky contact with the substrate.

[0022] In one embodiment of the present disclosure, the method for manufacturing the light detector further includes forming a groove on the absorption layer, wherein the top view shape of the groove is at least one of a comb shape, a tree shape, a mesh shape, or a spiral shape; and plating an upper electrode layer in the groove so that the upper electrode layer forms an ohmic contact or a Schottky contact with the absorption layer.

[0023] In one embodiment of the present disclosure, the method for manufacturing a light detector further includes forming a buffer layer on the substrate; and forming an absorption layer on the buffer layer.

[0024] In one embodiment of the present disclosure, the method for manufacturing the light detector further includes forming a capping layer on the absorption layer; patterning the capping layer to form an opening exposing the absorption layer; and coating an upper electrode layer in the opening.

[0025] In one embodiment of the present disclosure, an upper electrode layer is plated on the absorption layer so that an ohmic contact or a Schottky contact is formed between the upper electrode layer and the absorption layer.

[0026] In the above-mentioned embodiments of the present disclosure, since the absorption layer of the light detector includes a material whose electron mobility is greater than twice the hole mobility, the great difference in electron-hole mobility can be used to generate photocurrent. Therefore, it can operate independently at room temperature without the assistance of a cooling system, and can also operate under zero bias, thereby providing far-infrared detection with high detectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] When read together with the accompanying drawings, the aspects of the present disclosure can be best understood from the following embodiments. Note that according to standard practice in this industry, various features are not drawn to scale. In fact, the size of various features may be arbitrarily increased or reduced for clarity of discussion.

[0028] Figure 1 A cross-sectional view of a light detector according to one embodiment of the present disclosure is shown;

[0029] Figure 2 A cross-sectional view of a light detector according to another embodiment of the present disclosure is shown;

[0030] Figure 3 A three-dimensional diagram of a light detector according to another embodiment of the present disclosure is shown;

[0031] Figure 4 A perspective view of a light detector according to another embodiment of the present disclosure is shown;

[0032] Figure 5 A perspective view of a light detector according to another embodiment of the present disclosure is shown;

[0033] Figure 6 A cross-sectional view of a light detector according to one embodiment of the present disclosure is shown;

[0034] Figure 7 FIG. 4 is a flow chart showing a method for manufacturing a light detector according to an embodiment of the present disclosure.

[0035]

Explanation of symbols

[0036] 100,100a,100b,100c,100d,100e: Light detector

[0037] 110: Lower electrode layer

[0038] 120,120a: Absorption layer

[0039] 122: Interface area

[0040] 124: Groove

[0041] 126: Photogenerated positive charge region

[0042] 130, 130a: upper electrode layer

[0043] 131: Boundary

[0044] 132: Interface

[0045] 140:Substrate

[0046] 150: buffer layer

[0047] 160: Covering layer

[0048] E: Electric field

[0049] S1, S2, S3: Steps DETAILED DESCRIPTION

[0050] The following disclosed embodiments provide many different embodiments, or examples, for implementing the different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present invention. Of course, these examples are only examples and are not intended to be limiting. In addition, the present invention may repeat element symbols and / or letters in each example. This repetition is for the purpose of simplicity and clarity, and does not itself specify the relationship between the various embodiments and / or configurations discussed.

[0051] Spatially relative terms such as "below," "beneath," "lower," "above," "upper," and the like may be used herein for descriptive purposes to describe the relationship of one element or feature to another element or feature as illustrated in the accompanying drawings. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation illustrated in the accompanying drawings. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should likewise be interpreted accordingly.

[0052] Figure 1 FIG. 1 is a cross-sectional view of a light detector 100 according to an embodiment of the present disclosure. Figure 1The light detector 100 includes a lower electrode layer 110, an absorption layer 120, and an upper electrode layer 130. The absorption layer 120 is located on the lower electrode layer 110, wherein the absorption layer 120 includes an electron mobility greater than 300 cm 2 / Vs is also greater than twice the hole mobility, and the absorption layer 120 is configured to generate photocurrent by utilizing the large difference between electron mobility and hole mobility. The upper electrode layer 130 is located on the absorption layer 120, and is configured to absorb electrons e in the photocurrent. When a semiconductor or semi-metal material (such as the absorption layer 120) is excited by light L, electron-hole pairs are formed. At this time, because the electron mobility of certain specific materials (to be described in detail below) is high enough and very different from the hole mobility, the electrons will scatter and diffuse much faster than the holes. When electron holes are generated around the upper electrode layer 130 (for example, the boundary 131 of the upper electrode layer 130 and the interface 132 between the upper electrode layer 130 and the absorption layer 120) after being exposed to light, the fast electrons ( Figure 1 e) above will enter the upper electrode layer 130 and leave slow holes ( Figure 1 h), these holes that have lost electrons will form positive charges around the upper electrode layer 130, and compared with the lower electrode layer 110 without light, a vertical downward electric field E can be generated inside the device, thereby promoting the flow of carriers inside the absorption layer 120 to generate photocurrent. Representative materials with high electron mobility and a large gap between electron mobility and hole mobility include indium arsenide (InAs), indium antimonide (InSb), indium phosphide (InP), gallium arsenide (GaAs), gallium antimonide (GaSb), gallium indium arsenide (In 0.53 Ga 0.47 As), mercury cadmium telluride (Hg 1-x Cd x Te), cadmium arsenide (Cd3As2), a combination of the above materials, the above alloys or other suitable materials. Table 1 shows the electron mobility and hole mobility of the above materials at room temperature:

[0053] Material <![CDATA[Electron mobility (cm 2 / Vs)]]> <![CDATA[Hole mobility (cm 2 / Vs)]]> Indium Arsenide 30000 200 Indium Antimonide 80000 800 Indium Phosphide 4000 100 Gallium Arsenide 8500 400 Gallium Antimonide 5000 1000 Gallium Indium Arsenide 13800 500 Mercury Cadmium Telluride 10000 100 Cadmium Arsenide 15000 500

[0054] Table 1

[0055] As can be seen from Table 1, the above materials have a large difference between electron mobility and hole mobility at room temperature, and the electron mobility is at least twice as much as the hole mobility, and even a hundred times as much as that of indium antimonide. Therefore, they can be used as the absorption layer 120 of the light detector 100. The lower electrode layer 110 is configured to provide electrons to form a complete current loop in the light detector 100. In some embodiments, an ohmic contact is formed between the upper electrode layer 130 and the absorption layer 120. In some embodiments, an ohmic contact is formed between the absorption layer 120 and the lower electrode layer 110, and the lower electrode layer 110 is covered by the absorption layer 120. The formation of ohmic contacts between the upper electrode layer 130 and the absorption layer 120 and between the lower electrode layer 110 and the absorption layer 120 can improve the electron collection efficiency of the entire light detector 100. By appropriately doping the absorption layer 120 with holes (P-type), the device resistance can be reduced and the photocurrent can be increased, thereby achieving a higher detection rate and sensitivity. Appropriate P-type doping can also prevent the loss of forward photocurrent (towards the lower electrode layer 110) caused by the reverse thermal current (towards the upper electrode layer 130) generated by the Schottky contact when the absorption layer 120 is in the N-type semiconductor state after being illuminated, and the reverse photocurrent (towards the upper electrode layer 130) generated.

[0056] In addition to the above-mentioned ohmic contact manufacturing method, a Schottky contact can also be formed between the upper electrode layer 130 and the absorption layer 120. Because the absorption layer 120 generally uses a P-type semiconductor, when the P-type semiconductor forms a Schottky junction with the metal of the upper electrode layer 130, its built-in electric field direction will point to the semiconductor absorption layer 120. This built-in electric field E will accelerate the photoelectrons into the metal end when electron holes are generated by light, and at the same time block the photoholes from entering the upper electrode layer 130. This design can reduce the effect of contact resistance on photoelectron blocking when perfect ohmic contact is difficult to make, increase the probability of photoelectrons entering the electrode, and further improve the efficiency of photovoltage and photocurrent generation. However, this design is not applicable to the junction of the lower electrode layer 110 and the absorption layer 120. The junction of the lower electrode layer 110 is still mainly ohmic contact. Unless the total resistance of the device is too small, the total resistance of the device can still be increased and thermal noise can be reduced by increasing the contact resistance through Schottky contact, adding a blocking layer, etc.

[0057] Since the absorption layer 120 of the light detector 100 includes a material whose electron mobility is greater than twice the hole mobility, the great difference in electron-hole mobility can be used to generate photocurrent. Therefore, the light detector 100 can operate independently at room temperature without the assistance of a cooling system and an external bias voltage, thereby providing high detection rate and high resolution far-infrared detection.

[0058] Figure 2FIG. 1 is a perspective view of a light detector 100 a according to another embodiment of the present disclosure. Figure 2 The absorption layer 120a can be a single material, or the inner region near the surface contains a semiconductor-semiconductor, semiconductor-semimetal or semimetal-semimetal junction region 122 with a built-in electric field downward. The junction region 122 can be, for example, an NP junction, a NIP junction, an IP junction, or a P - P junction or PP + The purpose of the junction region 122 is to generate electron-hole pair separation after absorbing photons (this layer may also be called an electron-hole separation layer). Then, the fast electrons will enter the upper electrode layer 130 on the upper surface, leaving the slow holes. The spatial position of these holes that have lost electrons is still closer to the upper surface of the absorption layer 120a. Therefore, in addition to the above Figure 1 The boundary 131 of the upper electrode layer 130 and the holes near the interface 132 (such as Figure 1 h or Figure 2 In addition to the upper h), these additional holes generated by the junction region 122 ( Figure 2 The lower h) can further increase the amount of positive charges, thereby strengthening the downward electric field E and photocurrent in the vertical direction of the absorption layer 120 after illumination.

[0059] Figure 3 FIG. 1 is a perspective view of a light detector 100 b according to another embodiment of the present disclosure. Figure 3 The light detector 100b further includes a substrate 140. The substrate 140 is located between the absorption layer 120 and the lower electrode layer 110. In this embodiment, the top view shape of the upper electrode layer 130 is a comb shape. The reason for making such a shape is that at the edge of the upper electrode layer 130 (see Figure 1 ) has the best efficiency in absorbing electrons, and therefore can generate the strongest electric field E (refer to Figure 1 ). Therefore, by designing the top view shape of the upper electrode layer 130 to be comb-shaped, the overall edge length of the comb-shaped portion of the upper electrode layer 130 can be lengthened within a limited area, thereby improving the efficiency of the photocurrent generated by the large difference between the electron mobility and the hole mobility. In some embodiments, the top view shape of the upper electrode layer 130 can also be a tree-like, mesh-like, spiral-like, etc., but the present disclosure is not limited thereto. In some embodiments, the light detector 100b further includes a buffer layer 150, and the buffer layer 150 is located between the substrate 140 and the absorption layer 120. If the material of the absorption layer 120 is lattice-mismatched with the material of the substrate 140, a layer of buffer layer 150 can be used to alleviate this problem. The material of the buffer layer 150 can include cadmium zinc telluride (CdZnTe), but the present disclosure is not limited thereto.

[0060] Figure 4FIG. 1 is a perspective view of a light detector 100c according to another embodiment of the present disclosure. Figure 4 , the light detector 100c includes a lower electrode layer 110, an absorption layer 120, an upper electrode layer 130a, a substrate 140 and a buffer layer 150. Figure 3 The difference between the embodiment of the present invention and the embodiment of the present invention is that, in the present embodiment, the top view shape of the upper electrode layer 130a is a rectangle, and the material of the upper electrode layer 130a is a thin film containing transparent conductive materials such as indium tin oxide (ITO) or aluminum zinc oxide (AZO). In the present embodiment, the entire upper electrode layer 130a of the transparent conductive material can be used as an area for collecting photoelectrons. Because the upper electrode layer 130a contains a transparent conductive material, the absorption layer 120 below can be illuminated by light, and the photoelectrons excited by the light are absorbed by the electrode composed of the transparent conductive material, thereby generating a photocurrent.

[0061] Figure 5 FIG. 1 is a perspective view of a light detector 100d according to another embodiment of the present disclosure. Figure 5 , the light detector 100d includes a lower electrode layer 110, an absorption layer 120, an upper electrode layer 130, a substrate 140 and a buffer layer 150. Figure 3 The difference between the embodiment of the present invention and the embodiment of the present invention is that, in the present embodiment, the light detector 100d further includes a capping layer 160, which is located on the absorption layer 120 and surrounds the upper electrode layer 130. The capping layer 160 is configured to prevent the surface of the absorption layer 120 from directly contacting the air and reduce the defect density on the surface of the absorption layer 120. The material of the capping layer 160 may include cadmium zinc telluride (CdZnTe) or other insulating materials, but the present disclosure is not limited thereto.

[0062] Figure 6 FIG. 1 is a cross-sectional view of a light detector 100 e according to an embodiment of the present disclosure. Figure 6 The photodetector 100e includes a lower electrode layer 110, an absorption layer 120b, and an upper electrode layer 130. The absorption layer 120b is located on the lower electrode layer 110, and the upper electrode layer 130 is located on the absorption layer 120b, and is configured to absorb electrons e in the photocurrent. Figure 1The difference between the embodiments is that, in this embodiment, the absorption layer 120b has a groove 124, and a portion of the upper electrode layer 130 is located in the groove 124. Since the entry of photoelectrons into the upper electrode layer 130 is driven by a spontaneous thermal scattering mechanism, and the number of photoelectrons entering the electrode is determined by their average collision distance (mean collision length), the greater the electron mobility, the longer the average collision distance, which means that more scattered photoelectrons can enter the electrode. However, in general, the average collision distance of electrons is much less than 1 micron, which results in a shallower depth of the positive charge generation region (active region) in the present disclosure. However, the light penetration depth is in the absorption layer 120 (such as Figure 1 The internal quantum efficiency of the light detector 100 is low. Therefore, the groove 124 of the upper electrode layer 130 pattern can be dug out in the absorption layer 120b by etching, and then the metal electrode is filled into the groove 124. In this way, the range of electrons that can be collected will no longer be limited to the area around the upper electrode layer 130 near the surface (such as Figure 1 The depth of the upper electrode layer 130 may not be greater than the boundary 131 of the upper electrode layer 130, but may increase as the depth of the upper electrode layer 130 increases (such as the depth of the photogenerated positive charge region 126).

[0063] It should be understood that the connection relationship, materials and functions of the components described above will not be repeated, and will be described first. In the following description, a method for manufacturing a light detector will be described.

[0064] Figure 7 A flow chart of a method for manufacturing a light detector according to one embodiment of the present disclosure is shown. Figure 7 A method for manufacturing a light detector comprises the following steps: first, in step S1, providing an absorption layer, wherein the absorption layer comprises an electron mobility greater than 300 cm 2 / Vs is also greater than twice the hole mobility, and the absorption layer is configured to utilize the huge difference between electron mobility and hole mobility to generate photovoltage and thus form photocurrent; then in step S2, an upper electrode layer is plated on the absorption layer, wherein the upper electrode layer is configured to absorb scattered high-speed photoelectrons and destroy electrical neutrality around the upper electrode layer, causing positive charge accumulation of holes to generate photovoltage; finally in step S3, a lower electrode layer is formed so that the absorption layer is located between the upper electrode layer and the lower electrode layer.

[0065] In some embodiments, the method for manufacturing a light detector is not limited to the above steps S1 to S3. For example, each of steps S1 to S3 may include other more detailed steps. In some embodiments, steps S1 to S3 may further include other steps between two preceding and following steps, or may further include other steps before step S1 and further include other steps after step S3. Alternatively, some steps between steps S1 to S3 may be repeated. In the following description, at least the above steps will be described in detail.

[0066] Reference Figure 3 ,exist Figure 3 In an embodiment, before forming the absorption layer 120 on the substrate 140, a buffer layer 150 is first formed on the substrate 140. Then, the absorption layer 120 is formed. The formation of the absorption layer 120 includes using molecular beam epitaxy (MBE), chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), liquid phase epitaxy (LPE), a combination of the above, or other suitable methods. Alternatively, in other embodiments, the buffer layer 150 may not be formed, but the substrate 140 may be implanted or diffused to form the absorption layer 120 inside the substrate 140, but the present disclosure is not limited to this. The absorption layer 120 formed by ion implantation or diffusion can be formed as follows. Figure 2 The absorption layer 120a including the junction region 122 of the embodiment may also be doped by ion implantation or diffusion.

[0067] In some embodiments (such as Figure 5 Then, a covering layer 160 is formed on the absorption layer 120; then, the covering layer 160 is patterned to form an opening exposing the absorption layer 120; and an upper electrode layer 130 is plated on the absorption layer 120 in the opening. When the opening of the covering layer 160 is comb-shaped when viewed from above, the upper electrode layer 130 is plated on the absorption layer 120 in the opening so that the upper electrode layer 130 is comb-shaped when viewed from above, and the upper electrode layer 130 forms an ohmic contact or a Schottky contact with the absorption layer 120. In other embodiments, the covering layer 160 may not be formed and the upper electrode layer 130 may be directly formed (such as Figure 3 Implementation method) or 130a (such as Figure 4 implementation method).

[0068] Next, the lower electrode layer 110 is formed so that the absorption layer 120 is located between the upper electrode layer 130 and the lower electrode layer 110. Figure 1 In some embodiments (such as Figure 3 In the embodiment of the present invention, the lower electrode layer 110 is located on the surface of the substrate 140 facing away from the absorption layer 120. This step allows the lower electrode layer 110 to form an ohmic contact with the absorption layer 120 or the substrate 140. Different from the upper electrode layer 130, the lower electrode layer 110 is evenly distributed throughout the entire layer.

[0069] The foregoing summarizes the features of several embodiments so that those skilled in the art can better understand the aspects of the present disclosure. Those skilled in the art will appreciate that they can easily use the present disclosure as a basis for designing or modifying other processes and structures to achieve the same purposes and / or achieve the same advantages as the embodiments described herein. Those skilled in the art will also appreciate that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and modifications herein without departing from the spirit and scope of the present disclosure.

Claims

1. A light detector, characterized in that: Include: The lower electrode layer; An absorption layer is located on the lower electrode layer, wherein the absorption layer comprises an electron mobility greater than 300 cm 2 / Vs is greater than twice of its hole mobility, and the absorption layer is configured to generate a photocurrent by utilizing the difference between the electron mobility and the hole mobility; as well as An upper electrode layer is located on the absorption layer and is configured to absorb electrons in the photocurrent.

2. The light detector according to claim 1, wherein: The absorption layer includes a semiconductor-semiconductor junction, a semiconductor-semimetal junction, a semimetal-semimetal junction or a combination thereof with a built-in electric field downward.

3. The light detector according to claim 1, wherein: The top view shape of the upper electrode layer is at least one of a comb shape, a tree shape, a mesh shape or a spiral shape, and the upper electrode layer forms an ohmic contact or a Schottky contact with the absorption layer.

4. The light detector according to claim 3, wherein: The upper electrode layer is located in a groove of the absorption layer.

5. The light detector according to claim 1, wherein: Also includes: a substrate, located between the absorption layer and the lower electrode layer; and A buffer layer is located between the substrate and the absorption layer.

6. The light detector according to claim 1, wherein: The top view shape of the upper electrode layer is a rectangle, and the upper electrode layer is a transparent conductive film including indium tin oxide (ITO) or aluminum zinc oxide (AZO).

7. The light detector according to claim 1, wherein: Also includes: A covering layer is located on the absorption layer and surrounds the upper electrode layer.

8. A method for manufacturing a light detector, characterized in that: Include: An absorption layer is provided, wherein the absorption layer comprises an electron mobility greater than 300 cm 2 / Vs is greater than twice of its hole mobility, and the absorption layer is configured to generate a photovoltage and thus a photocurrent by utilizing the difference between the electron mobility and the hole mobility; Plating an upper electrode layer on the absorption layer, wherein the upper electrode layer is configured to absorb scattered photoelectrons and destroy electrical neutrality around the upper electrode layer, causing positive charge accumulation of holes to generate photovoltage; as well as A lower electrode layer is formed so that the absorption layer is located between the upper electrode layer and the lower electrode layer.

9. The method for manufacturing a light detector according to claim 8, wherein: The absorbent layer is provided comprising: The absorption layer is formed on a substrate.

10. The method for manufacturing a light detector according to claim 9, wherein: Forming the lower electrode layer comprises: The lower electrode layer is formed on a surface of the substrate facing away from the absorption layer.

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