阅读说明：本技术 工作波长与入射光角度无关的热电子光探测器及制造方法 (Thermal electron photodetector with working wavelength independent of incident light angle and manufacturing method thereof ) 是由 邵伟佳 张程 李孝峰 于 2020-06-10 设计创作，主要内容包括：本发明涉及一种工作波长与入射光角度无关的热电子光探测器及制造方法,包括基底、第一金属薄膜、电极中间层、第二金属薄膜、微腔中间层和分布式布拉格反射镜,且所述第一金属薄膜、电极中间层、第二金属薄膜、微腔中间层和分布式布拉格反射镜依次叠加设置所述基底上,所述第一金属薄膜、电极中间层、第二金属薄膜、微腔中间层以及分布式布拉格反射镜组成光学微腔。本发明有效光学吸收强且工作波长随入射光角度变化而不会发生变化。(The invention relates to a thermionic photodetector with a working wavelength irrelevant to an incident light angle and a manufacturing method thereof. The invention has strong effective optical absorption and the working wavelength can not change along with the angle change of incident light.)

1. A thermionic photodetector having a wavelength of operation independent of the angle of incident light, comprising: the optical micro-cavity comprises a substrate, a first metal film, an electrode intermediate layer, a second metal film, a micro-cavity intermediate layer and a distributed Bragg reflector, wherein the first metal film, the electrode intermediate layer, the second metal film, the micro-cavity intermediate layer and the distributed Bragg reflector are sequentially stacked on the substrate, and the first metal film, the electrode intermediate layer, the second metal film, the micro-cavity intermediate layer and the distributed Bragg reflector form an optical micro-cavity.

2. A thermionic photodetector having a wavelength of operation independent of the angle of incident light as claimed in claim 1 wherein: the substrate is any one of glass sheet, plastic, ceramic, metal and wood.

3. A thermionic photodetector having a wavelength of operation independent of the angle of incident light as claimed in claim 1 wherein: the first metal film and the second metal film are made of the same material.

4. A thermionic photodetector having an operating wavelength independent of the angle of incident light as claimed in claim 3 wherein: the first metal film is any one of a gold film, a silver film, a copper film and an aluminum film.

5. A thermionic photodetector having a wavelength of operation independent of the angle of incident light as claimed in claim 1 wherein: the electrode intermediate layer adopts any one of a zinc oxide film, an aluminum oxide film and a titanium dioxide film.

6. A thermionic photodetector having a wavelength of operation independent of the angle of incident light as claimed in claim 1 wherein: the microcavity intermediate layer is made of any one of a germanium film, a tellurium film and a silicon film.

7. A thermionic photodetector having a wavelength of operation independent of the angle of incident light as claimed in claim 1 wherein: the distributed Bragg reflector is composed of two layers of oxide films which are periodically and alternately arranged.

8. A thermionic photodetector having an operating wavelength independent of the angle of incident light as claimed in claim 7 wherein: the two layers of oxide films are formed by any two of a titanium dioxide film, a zinc oxide film, a silicon dioxide film and an alumina film.

9. A method of fabricating a thermionic photodetector having a wavelength of operation independent of the angle of incident light, for use in fabricating a thermionic photodetector as claimed in any one of claims 1 to 8, comprising the steps of:

step S1: plating a first metal film on the substrate by an electron beam evaporation method;

step S2: depositing an electrode intermediate layer on the first metal film by using an atomic layer deposition method;

step S3: plating a second metal film on the electrode intermediate layer by using an electron beam evaporation method;

step S4: depositing a microcavity intermediate layer on the second metal film by an electron beam evaporation method;

step S5: and growing a plurality of oxide films which are periodically and alternately arranged on the microcavity intermediate layer by a magnetron sputtering method to form the distributed Bragg reflector.

10. A method of fabricating a thermionic photodetector having an operating wavelength independent of the angle of incident light as claimed in claim 9, wherein: before the step S1, a step of cleaning the substrate is further included.

Technical Field

The invention relates to the technical field of thermionic photodetectors, in particular to a thermionic photodetector with a working wavelength independent of an incident light angle and a manufacturing method thereof.

Background

The thermionic photodetector is a sub-forbidden band photodetector, and has the advantages of short response time, wide detection frequency spectrum, capability of room-temperature operation and the like. The performance of a thermionic photodetector is characterized by responsivity, i.e., the current output of the device per incident optical power. Structurally, there are two types of metal-semiconductor junction thermo-electron photo-detectors and metal-dielectric-metal junction thermo-electron photo-detectors.

In the metal-dielectric-metal junction thermionic optical detector, two layers of metal are used as optical absorption materials to jointly form an opaque metal layer, and are used as two electrodes of the detector to output an electric signal. The working principle of the metal-medium-metal junction thermionic optical detector can be divided into four steps: the first step is as follows: when an incident light signal irradiates on a detector, optical absorption is caused in the opaque metal layer, but due to the skin depth of the metal, the optical absorption of the first layer of metal electrode is greater than that of the second layer of metal electrode, so that optical net absorption exists; the second step is that: electrons near the Fermi level in the metal are subjected to energy transition of incident photons to a high level to generate hot electrons in a non-thermodynamic equilibrium state; the third step: the generated hot electrons are freely diffused and transported in the metal to the metal-medium interface; the fourth step: the hot electrons successfully reaching the interface reach the counter electrode through the electrode intermediate layer to be collected, and the number of the hot electrons collected by the two electrodes is unequal due to optical net absorption to form an output current signal.

In order to enhance the performance index of the thermionic photodetector, a metal or medium micro-nano structure can be constructed, so that the absorption of incident light signals and the electrical transport of thermions are enhanced. However, while enhancing the performance index, the method has the disadvantages of complex process, high cost, difficulty in large-scale preparation and the like. On the contrary, the planar thermionic photodetector has the advantages of simple process, low cost, large-scale preparation and the like. However, no matter the micro-nano structure and the planar thermionic photodetector, the working wavelength of the device changes along with the change of the incident angle of the signal light, so that the practical application prospect of the thermionic photodetector can be weakened.

The existing plane type metal-medium-metal junction thermionic optical detector has two defects: firstly, the corresponding effective optical absorption of the opaque metal layer formed by two electrodes is weaker, because an optical microcavity is generally constructed by a planar multilayer structure, and Fabry-Perot resonance is formed in the microcavity to realize the perfect optical absorption. The optical microcavity consists of three components: the semi-transparent metal layer, the microcavity intermediate layer and the opaque metal layer, but the semi-transparent metal layer occupies a substantial portion of the optical absorption, resulting in a weaker effective optical absorption in both electrodes. Secondly, because the fabry-perot resonance is sensitive to the incident angle of the signal light, the working wavelength changes with the incident angle.

Disclosure of Invention

Therefore, the technical problem to be solved by the present invention is to overcome the problems of the prior art that the effective optical absorption is not strong and the operating wavelength varies with the angle of incident light, so as to provide a thermionic photodetector and a manufacturing method thereof, wherein the operating wavelength is independent of the angle of incident light, and the operating wavelength is strong and does not vary with the angle of incident light.

In order to solve the technical problem, the thermionic photodetector with the working wavelength irrelevant to the incident light angle comprises a substrate, a first metal film, an electrode intermediate layer, a second metal film, a microcavity intermediate layer and a distributed Bragg reflector, wherein the first metal film, the electrode intermediate layer, the second metal film, the microcavity intermediate layer and the distributed Bragg reflector are sequentially stacked on the substrate, and the first metal film, the electrode intermediate layer, the second metal film, the microcavity intermediate layer and the distributed Bragg reflector form an optical microcavity.

In one embodiment of the invention, the substrate is any one of a glass sheet, plastic, ceramic, metal, wood.

In one embodiment of the present invention, the first metal thin film and the second metal thin film are the same material.

In one embodiment of the present invention, the first metal thin film is any one of a gold thin film, a silver thin film, a copper thin film, and an aluminum thin film.

In an embodiment of the invention, the electrode intermediate layer is any one of a zinc oxide film, an aluminum oxide film and a titanium dioxide film.

In an embodiment of the present invention, the microcavity intermediate layer is made of any one of a germanium film, a tellurium film, and a silicon film.

In one embodiment of the present invention, the distributed bragg reflector is composed of two oxide films alternately arranged periodically.

In one embodiment of the present invention, the two oxide films are formed of any two of a titanium oxide film, a zinc oxide film, a silicon dioxide film, and an aluminum oxide film.

The invention also provides a method for manufacturing the thermionic photodetector, wherein the working wavelength of the thermionic photodetector is irrelevant to the incident light angle, and the method is used for manufacturing the thermionic photodetector and comprises the following steps: plating a first metal film on the substrate by an electron beam evaporation method; depositing an electrode intermediate layer on the first metal film by using an atomic layer deposition method; plating a second metal film on the electrode intermediate layer by using an electron beam evaporation method; depositing a microcavity intermediate layer on the second metal film by an electron beam evaporation method; and growing a plurality of oxide films which are periodically and alternately arranged on the microcavity intermediate layer by a magnetron sputtering method to form the distributed Bragg reflector.

In one embodiment of the present invention, before the step S1, a step of cleaning the substrate is further included.

Compared with the prior art, the technical scheme of the invention has the following advantages:

the thermionic photodetector with the working wavelength irrelevant to the incident light angle and the manufacturing method have very high responsivity which is 2-3 times higher than that of an international product in general; the design is simple and clear, the structure is novel, the process is simple, the price is low, the material is not limited to a certain material, and the application range of the thermionic photodetector is expanded; moreover, the working wavelength range can be changed by adjusting the geometrical parameters of the structure, such as the thickness of the middle layer of the microcavity, so that the method has good adaptability.

Drawings

In order that the present disclosure may be more readily and clearly understood, reference is now made to the following detailed description of the embodiments of the present disclosure taken in conjunction with the accompanying drawings, in which

FIG. 1 is a schematic diagram of a thermionic photodetector of the present invention having a wavelength of operation independent of the angle of incident light;

FIG. 2 is a schematic diagram of the variation of the polarization state and the operating wavelength of an incident optical signal according to the present invention;

FIG. 3 is a flow chart of a method of fabricating a thermionic photodetector having a wavelength of operation independent of the angle of incident light in accordance with the present invention.

The specification reference numbers indicate: 11-substrate, 12-first metal film, 13-electrode interlayer, 14-second metal film, 15-microcavity interlayer, 16-distributed Bragg reflector.

Detailed Description