CN107507873A - A kind of vacuous solar energy electrooptical device - Google Patents

Abstract

The invention provides a vacuum solar photoelectric converter, comprising a transmissive GaAlAs/GaAs photocathode component, an indium sealing material, a first Kovar alloy, a second Kovar alloy, a cylindrical ceramic cavity and a diamond film anode component; a cathode component From top to bottom, it is composed of glass window, anti-reflection layer, GaAlAs window layer, GaAs emission layer, and Cs/O active layer; the anode assembly is composed of diamond film layer, Si substrate layer, and glass window from the bottom; the cathode assembly 1. Channels are arranged between the diamond film anode components, each component in the cathode component is connected with the first kovar alloy through the indium sealing material, and each component in the anode component is connected with the second kovar alloy through the indium sealing material, and the first kovar alloy is connected with each other through the indium sealing material The alloy and the second Kovar alloy are connected through a cylindrical ceramic cavity, and a vacuum cavity is formed between the two poles.

Description

A vacuum solar photoelectric conversion device

technical field

The invention relates to a solar cell and semiconductor technology, in particular to a vacuum solar photoelectric conversion device.

Background technique

As a renewable energy with huge energy storage, solar energy has always been the focus of research on green new energy around the world. From the perspective of the distribution of solar energy resources in the world, China is also a country with very rich solar energy resources, with an average annual total solar radiation of more than 6000MJ/m ² . At present, there are many ways to utilize solar energy. Among them, solar power generation is an important method of utilizing solar energy. There are two relatively mature methods of solar power generation technology: photovoltaic power generation and photothermal power generation. The photoelectric conversion efficiency of photovoltaic power generation can reach more than 28%, but the cost of power generation is relatively high, while the power generation efficiency of photothermal power generation is between 12% and 20%. Neither of these approaches fully utilizes the energy of the solar spectrum. At the same time, conventional solar conversion devices are all solid-state structures, and can only use a part of the energy in the solar spectrum, and cannot fully utilize the energy of the entire spectrum. At the same time, conventional solar energy conversion devices are all solid-state structures, and can only utilize a part of the energy in the solar spectrum, and cannot fully utilize the energy of the entire spectrum.

Contents of the invention

The object of the present invention is to provide a vacuum solar photoelectric converter, comprising a transmissive GaAlAs/GaAs photocathode assembly, an indium sealing material, a first Kovar alloy, a second Kovar alloy, a cylindrical ceramic chamber and a diamond film anode assembly; The transmissive GaAlAs/GaAs photocathode component is composed of glass window, anti-reflection layer, GaAlAs window layer, GaAs emission layer, and Cs/O active layer from top to bottom; the diamond film anode component is composed of diamond film layer, Composed of Si substrate layer and glass window; a channel is set between the transmissive GaAlAs/GaAs photocathode assembly and the diamond film anode assembly, and each component in the transmissive GaAlAs/GaAs photocathode assembly is connected to the first Kovar alloy through an indium sealing material, The components in the diamond thin film anode assembly are connected to the second kovar alloy through the indium sealing material, the first kovar alloy and the second kovar alloy are connected through a cylindrical ceramic cavity, and a vacuum cavity is formed between the two poles.

The vacuum solar photoelectric conversion device proposed in the present invention uses a vacuum structure to separate the cathode and the anode. When the cathode absorbs the incident solar radiation energy, electrons can be emitted from the cathode, and the cathode is irradiated by sunlight to increase the temperature of the cathode. With the help, the photoelectron emission efficiency of the cathode can be further improved, thereby making full use of the sun's light energy and heat energy, and greatly improving the conversion efficiency of solar energy. The negative electrode in the present invention adopts GaAlAs/GaAs photocathode, the acceleration of its built-in electric field and the low interfacial recombination rate can further improve the cathode outgoing current density; The potential difference makes the photogenerated electrons fully collected by the anode.

The present invention will be further described below in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 is a package structure diagram of the vacuum solar photoelectric conversion device of the present invention.

Fig. 2 is a working principle diagram of the vacuum solar photoelectric conversion device of the present invention.

Fig. 3 is an experimental quantum efficiency curve diagram of the transmissive GaAlAs/GaAs photocathode of the vacuum solar photoelectric conversion device of the present invention.

detailed description

Combined with Figure 1, a vacuum solar photoelectric conversion device, including a transmissive GaAlAs/GaAs photocathode assembly [1], an indium sealing material [2], a first Kovar alloy [3-1], and a second Kovar alloy [3 -2], cylindrical ceramic cavity [4] and diamond film anode [10], the transmissive GaAlAs/GaAs photocathode component is connected with the first Kovar alloy 3-1 through the indium sealing material 2, and the first Kovar alloy 3- 1 is connected to the second Kovar 3-2 through a cylindrical ceramic cavity, and finally the second Kovar 3-2 is connected to the diamond anode 10 through the indium sealing material 2. The first Kovar 3-1 can serve as the pin of the transmissive GaAlAs/GaAs photocathode assembly 1, and the second Kovar 3-2 serves as the pin of the diamond film anode assembly; the transmissive GaAlAs/GaAs photocathode assembly 1 From top to bottom, it is composed of Corning 7056 ^# glass window [5], anti-reflection layer [6], GaAlAs window layer [7], GaAs emission layer [8] and Cs/O active layer [9] in sequence. The low work function diamond anode assembly is mainly composed of diamond film layer [11], Si substrate layer [12] and Corning 7056 ^# glass window [13]. The first Kovar alloy 3-1 can serve as the pin of the transmissive GaAlAs/GaAs photocathode assembly 1, and the second Kovar alloy 3-2 can serve as the pin of the diamond film anode collecting electrons in the vacuum photoelectric conversion device, GaAlAs/GaAs The photocathode assembly and the diamond film anode form a flat capacitor, and the entire diode is a cylindrical structure.

Furthermore, the total thickness of the Corning 7056 ^# glass window is between 2 and 6 mm.

Further, the total thickness of the antireflection layer is between 100nm and 200nm.

Further, the GaAlAs buffer layer is epitaxially grown on the anti-reflection layer with a thickness of _1-2um , and the Al composition of the _Ga1 -xAlxAs buffer layer decreases linearly from the anti-reflection layer to the direction of the GaAs emission layer from a maximum of 0.6 to 0.9 to 0.

Further, the concentration doping of the GaAs emitting layer is distributed in an exponential doping form, and the doping concentration range is also controlled between 1.0×10 ¹⁹ -1×10 ¹⁸ cm ⁻³ .

Further, the Cs/O active layer is tightly adsorbed on the surface of the GaAs emission layer through an ultra-high vacuum activation process, and the thickness is between 0.5-1.5 nm.

Further, the distance between the two poles is between 2cm and 5cm.

Further, for the diamond thin film anode, firstly, the diamond particles are deposited on the silicon substrate through the electrophoresis process, and the diamond film is formed by the hot filament CVD method. During the preparation, the substrate temperature is controlled at 850 ° C, the filament is at 2100 ° C, and the pressure is 1500 Pa. , and finally form amorphous carbon on the surface to achieve a negative electron affinity, and finally obtain a work function of less than 1.0eV, and the total thickness is between 2 and 4um.

In conjunction with Fig. 2, the working principle of the present invention is: sunlight is incident from the substrate surface of the transmissive GaAlAs/GaAs cathode, and the photoelectrons generated by the cathode material absorbing the incident photons reach the emission surface of the cathode after internal transport, because the temperature of the cathode rises under the light High, part of the photoelectrons absorbing heat can gain enough kinetic energy and then overcome the surface barrier to escape into the vacuum, be collected by the low work function diamond film anode and output as electrical energy, so that the solar energy can be successfully converted into electrical energy. The GaAlAs/GaAs cathode with variable composition and variable doping structure can accelerate the movement of electrons through the built-in electric field. Due to its wide band gap and low work function, the diamond film can effectively collect the emitted electrons from the cathode and increase the potential difference between the two electrodes. Thereby improving the conversion efficiency of the device.

Combined with Figure 3, photons of different wavelengths in the range of 300-900nm are incident on the transmissive GaAlAs/GaAs photocathode. After absorption, excitation, and transport in the cathode body, photoelectrons are emitted on the surface, resulting in a photoemission effect. At the same time The TEC sheet is used to heat the cathode to increase the temperature of the cathode and improve the photoelectric emission efficiency. As shown in Figure 3, in the logarithmic coordinate system, the horizontal coordinate is the wavelength, and the vertical coordinate is the quantum efficiency. It can be seen from Figure 3 that the response range of the quantum efficiency curve of the transmissive GaAlAs/GaAs photocathode is between 350 and 900 nm, which meets the requirements of the wide spectral response range of solar cells and can make full use of the solar radiation on the earth's surface. In addition, we found that when the temperature of the cathode increased from 20°C to 60°C, the corresponding quantum efficiency also increased to a certain extent, and we found that the quantum efficiency of the long-wave band was greatly affected by the temperature, because the photons in the long-wave band There are more low-energy electrons generated, so absorbing heat energy under heating conditions can increase kinetic energy, thereby increasing the number of emitted photoelectrons. In general, the experimental curve proves that the increase of cathode temperature can obtain higher photoelectric emission efficiency, so the vacuum solar photoelectric conversion device can obtain higher conversion efficiency in line with the original intention of the design, which is of great significance to the utilization of solar energy important meaning.

The anode material of the present invention can be nickel-aluminum alloy, and its work function is relatively high. The vacuum solar photoelectric conversion device can be completed by replacing the low work function diamond film anode, and a higher conversion efficiency can be obtained.

Claims (8)

1. a kind of vacuous solar energy electrooptical device, it is characterised in that including transmission-type GaAlAs/GaAs photocathode components [1], indium closure material [2], the first kovar alloy [3-1], the second kovar alloy [3-2], cylindrical ceramic chamber [4] and thin diamond Film anode assemblies [10]；

Transmission-type GaAlAs/GaAs photocathodes component [1] is from top to bottom by glass window [5], antireflection layer [6], GaAlAs windows Mouth layer [7], GaAs emission layers [8], Cs/O active coatings [9] are sequentially overlapped composition；

Diamond thin anode assemblies [10] feel sorrow for oneself and under by diamond film layer [11], Si substrate layers [12], glass window [13] Form；

Transmission-type GaAlAs/GaAs photocathodes component [1], diamond thin anode assemblies set passage between [10],

Each part in transmission-type GaAlAs/GaAs photocathodes component [1] passes through indium closure material [2] and the first kovar alloy [3-1] is connected,

Each part in diamond thin anode assemblies [10] is connected by indium closure material [2] with the second kovar alloy [3-2],

It is connected between first kovar alloy [3-1] and the second kovar alloy [3-2] by cylindrical ceramic chamber [4],

Vacuum cavity is formed between the two poles of the earth.

2. vacuum electrooptical device according to claim 1, it is characterised in that glass window [5] gross thickness 2~ Between 6mm.

3. vacuum electrooptical device according to claim 1, it is characterised in that antireflection layer [6] gross thickness 100~ Between 200nm.

4. vacuum electrooptical device according to claim 1, it is characterised in that the Al groups of the cushion [7] of Varied clearance Divide from antireflection layer toward GaAs emission layers direction and linearly decrease to zero by maximum 0.6~0.9, gross thickness is between 100~1000nm.

5. vacuum electrooptical device according to claim 1, it is characterised in that the doped in concentrations profiled of GaAs emission layers [8] According to exponential doping formal distribution, doping concentration scope is equally controlled 1.0 × 10¹⁹~1 × 10¹⁸cm^-3Between.

6. vacuum electrooptical device according to claim 1, it is characterised in that Cs/O active coatings [9] are true by superelevation Empty activation technology adsorbed close is on the surface of GaAs emission layers.

7. vacuum electrooptical device according to claim 1, it is characterised in that diamond network thin film positive pole component [10] obtain by the following method：

One layer of netted Si substrate layer [12] is grown on silica glass window [13],

Diamond particle is deposited on netted Si substrate layers [12] by electrophoresis, and diamond network is formed with filament CVD Film layer [11].

8. vacuum electrooptical device according to claim 1, it is characterised in that：Become component cushion [7] and varying doping GaAs emission layers [8] are grown using MOVCD modes, and foreign atom is zinc atom.