Laser photovoltaic cell and manufacturing method thereof

Abstract

The invention discloses a laser photovoltaic cell and a manufacturing method thereof, and relates to the technical field of photovoltaic cells. The laser photovoltaic cell comprises a supporting substrate, the upper surface of the supporting substrate is sequentially provided with a first buffer layer, a 1064nm laser cell, a component order buffer layer, an electrode contact layer, a 808nm laser cell, a current expansion layer and an ohmic contact layer, the ohmic contact layer is provided with a first electrode, the electrode contact layer is provided with a second electrode, and the first electrode is provided with a first electrode. And a third electrode is arranged on the lower surface of the supporting substrate. The double-waveband laser cell can be suitable for double-waveband structural design of 808nm and 1064nm laser at the same time, so that the applicability and the stability of the laser cell under different environmental conditions are improved.

Description

Technical Field

[0001] This invention relates to the technical field of photovoltaic cells, and more particularly to a laser photovoltaic cell and its manufacturing method. Background Technology

[0002] GaAs-based laser cells use laser light as the incident light source and are also known as photovoltaic power converters. Compared to broadband solar cells, GaAs-based laser cells exhibit higher photoelectric conversion efficiency under monochromatic light irradiation suitable for their bandgap. Furthermore, due to the tunable power of the laser, the cells can operate under high-power incident conditions, resulting in better output characteristics. For example, a single-junction GaAs-based laser cell can operate at an incident light wavelength of 808 nm and a power of 5 W / cm². 2 The photoelectric conversion efficiency can reach 53.23%. In addition, the laser battery has excellent electromagnetic interference resistance and insulation properties, which makes it widely used in spacecraft and other harsh environments.

[0003] Depending on the incident laser wavelength, laser cells are generally classified into 808nm and 1064nm types. 808nm laser cells belong to the near-infrared band and possess high energy transmission capabilities; however, their laser beam transmission efficiency in air is easily affected by atmospheric quality, exhibiting significant attenuation under poor atmospheric conditions. In contrast, 1064nm infrared laser cells experience less loss during atmospheric transmission and are more adaptable to different environments. Therefore, improving the applicability and stability of laser cells under various environmental conditions is of great significance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a laser photovoltaic cell and its manufacturing method, which can be applied to the dual-band structure design of 808nm and 1064nm lasers to improve the applicability and stability of the laser cell under different environmental conditions.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a laser photovoltaic cell, comprising a supporting substrate, wherein a first buffer layer, a 1064nm laser cell, a composition step change buffer layer, an electrode contact layer, an 808nm laser cell, a current spreading layer, and an ohmic contact layer are sequentially disposed on the upper surface of the supporting substrate, wherein a first electrode is disposed on the ohmic contact layer, a second electrode is disposed on the electrode contact layer, and a third electrode is disposed on the lower surface of the supporting substrate.

[0006] Preferably, the 808nm laser cell consists of at least one sub-cell, and the base region and emission region of each sub-cell are made of GaAs.

[0007] Preferably, the 1064nm laser cell consists of at least one sub-cell, and the base region and emission region of each sub-cell are made of GaInAs.

[0008] Preferably, the component step-change buffer layer is AlGaInAs, and the band gap of AlGaInAs is greater than the band gap of the base region and the emitter region of the neutron cell in a 1064nm laser cell.

[0009] Preferably, along the direction from the 808nm laser cell to the 1064nm laser cell, the step change buffer layer is sequentially composed of step change buffer layer 1, step change buffer layer 2... step change buffer layer (N-1), overshoot layer, and step change buffer layer N; let the lattice constants of the base regions of the 808nm laser cell and the 1064nm laser cell be K and L, respectively, and the lattice constants of the step change buffer layer 1, step change buffer layer 2... step change buffer layer (N-1), overshoot layer, and step change buffer layer N be a1, a2, ..., a... n-1 b and a n Satisfying: K <a1<...<a2<a n-1 n ≤L <b。

[0010] Preferably, the supporting substrate is electroplated copper.

[0011] Preferably, each sub-cell in the 808nm laser cell and the 1064nm laser cell independently includes a back field layer, a base region, an emission region, and a window layer, and the sub-cells are connected by tunnel junctions.

[0012] Preferably, the second electrode is ring-shaped, and the 808nm laser cell is located on the central axis of the second electrode.

[0013] Preferably, the distance between the second electrode and the 808nm laser cell is a, wherein a satisfies: 10μm≤a≤200μm.

[0014] Secondly, the present invention also provides a method for manufacturing a laser photovoltaic cell, comprising the following steps: (1) First, an ohmic contact layer, a current spreading layer, an 808nm laser cell, an electrode contact layer, a composition step change buffer layer, a 1064nm laser cell, and a first buffer layer are sequentially grown on the surface of a GaAs substrate to obtain an epitaxial layer. (2) Then the epitaxial layer is transferred to the support substrate and the GaAs substrate is removed; a first electrode is disposed on the upper surface of the ohmic contact layer, a second electrode is disposed on the upper surface of the electrode contact layer, and a third electrode is disposed on the lower surface of the support substrate.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:​ The present invention designs two types of laser cells in longitudinal series from the epitaxial structure. When the incident light is 808nm laser, the first electrode and the third electrode are connected; when the incident light is 1064nm laser, the second electrode and the third electrode are connected, thereby realizing photovoltaic power generation that can use both 808nm and 1064nm lasers. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the laser photovoltaic cell described in this invention.

[0017] Figure 2 This is a schematic diagram illustrating the structure of a neutron cell in a laser photovoltaic cell, as described in this invention. Detailed Implementation

[0018] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments, but the scope of protection and implementation of the present invention are not limited thereto.

[0019] Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0020] Example 1 This embodiment discloses a laser photovoltaic cell, such as Figure 1 As shown, the system includes a supporting substrate. On the upper surface of the supporting substrate, a first buffer layer, a 1064nm laser cell, a composition step change buffer layer, an electrode contact layer, an 808nm laser cell, a current spreading layer, and an ohmic contact layer are sequentially disposed. A first electrode is disposed on the upper surface of the ohmic contact layer, a second electrode is disposed on the upper surface of the electrode contact layer, and a third electrode is disposed on the lower surface of the supporting substrate. The second electrode is annular, and the 808nm laser cell is located on the central axis of the second electrode. The distance between the second electrode and the 808nm laser cell is 'a', where 'a' = 100μm.

[0021] This embodiment also discloses a method for manufacturing a laser photovoltaic cell, including the following steps: (1) An ohmic contact layer is grown on the upper surface of a GaAs substrate. The ohmic contact layer is a 500 nm thick GaAs substrate with a doping concentration of 5 × 10⁻⁶. 18 cm -3 ; (2) A current spreading layer is grown on the ohmic contact layer, wherein the current spreading layer is 800 nm GaInP with a doping concentration of 5 × 10⁻⁶. 18 cm -3 ; (3) An 808nm laser cell is grown inverted on the current spreading layer along the direction away from the substrate. The 808nm laser cell consists of a 30nm thick AlInP window layer, a 100nm thick GaAs emission region, a 3500nm thick GaAs base region, and a 100nm thick AlGaAs back field layer. (4) An electrode contact layer is grown on an 808nm laser cell. The electrode contact layer is a 500nm thick GaAs with a doping concentration of 5×10⁻⁶. 18 cm -3 ; (5) An inverted compositional gradient buffer layer is grown on the electrode contact layer, wherein the compositional gradient buffer layer is 2000 nm thick AlGaInAs with a doping concentration of 1×10⁻⁶. 18 cm -3 The band gap of AlGaInAs is larger than that of the base and emitter regions of the 1064nm laser cell. Along the direction from the 808nm laser cell to the 1064nm laser cell, the step-change buffer layer is sequentially composed of step-change buffer layer 1, step-change buffer layer 2, step-change buffer layer 3, step-change buffer layer 4, overshoot layer, and step-change buffer layer 5. The lattice constants of the base regions of the 808nm and 1064nm laser cells are 0.565nm and 0.573nm, respectively, and the lattice constants of step-change buffer layer 1, step-change buffer layer 2, step-change buffer layer 3, step-change buffer layer 4, overshoot layer, and step-change buffer layer 5 are 0.5666nm, 0.5682nm, 0.5698nm, 0.5714nm, 0.7449nm, and 0.573nm, respectively. (6) A 1064nm laser cell is grown inverted on the composition-level variable buffer layer. Along the direction away from the substrate, the 1064nm laser cell is composed of a 30nm thick AlInP window layer, a 100nm thick GaInAs emission region, a 3500nm thick GaInxAs base region, and a 100nm thick AlGaInAs back field layer. (7) A first buffer layer is grown on a 1064nm laser cell. The first buffer layer is a 500nm thick InGaAs with a doping concentration of 3×10⁻⁶. 18 cm -3 ; Obtain the epitaxial layer; (8) Then the epitaxial layer is transferred to the electroplated copper support substrate and the GaAs substrate is removed; a first electrode is disposed on the upper surface of the ohmic contact layer, the first electrode being a 4000nm thick Au; A second electrode is disposed on the upper surface of the electrode contact layer. The second electrode is Au with a thickness of 4000 nm. The distance between the second electrode and the 808 nm laser cell is 100 μm. A third electrode is disposed on the lower surface of an electroplated copper support substrate, wherein the third electrode is a 3000nm thick Au electrode. (9) Finally, antireflection films with a thickness of 120 nm are set on the surfaces of the 808 nm laser cell and the 1064 nm laser cell, respectively.

[0022] Example 2 The difference from Example 1 is that, as Figure 2 As shown, the 1064nm laser cell consists of six sub-cells, arranged sequentially from the support substrate as the first, second, third, fourth, fifth, and sixth sub-cells. All six sub-cells are connected in series via AlGaInAs tunnel junctions. The base and emitter regions of each sub-cell are made of GaInAs. Each sub-cell includes a back surface layer, a base region, an emitter region, and a window layer.

[0023] The 808nm laser cell consists of six sub-cells, numbered seventh, eighth, ninth, tenth, eleventh, and twelfth sequentially along the direction away from the supporting substrate. All six sub-cells are connected in series via AlGaAs tunnel junctions. The base and emitter regions of each sub-cell are made of GaAs. Each sub-cell includes a back surface layer, a base region, an emitter region, and a window layer.

[0024] The back surface layer, emission region, and window layer of each sub-cell in the 1064nm and 808nm laser cells are the same as in Example 1. The sum of the base region thickness of each sub-cell is 3000nm.

[0025] The present invention designs two types of laser cells in longitudinal series from the epitaxial structure. When the incident light is 808nm laser, the first electrode and the third electrode are connected; when the incident light is 1064nm laser, the second electrode and the third electrode are connected, thereby realizing photovoltaic power generation that can use both 808nm and 1064nm lasers.

[0026] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A laser photovoltaic cell, characterized in that, The device includes a support substrate, on the upper surface of which a first buffer layer, a 1064nm laser cell, a composition step change buffer layer, an electrode contact layer, an 808nm laser cell, a current spreading layer, and an ohmic contact layer are sequentially disposed. A first electrode is disposed on the ohmic contact layer, a second electrode is disposed on the electrode contact layer, and a third electrode is disposed on the lower surface of the support substrate.

2. The laser photovoltaic cell as described in claim 1, characterized in that, The 808nm laser cell consists of at least one sub-cell, and the base region and emission region of each sub-cell are made of GaAs.

3. The laser photovoltaic cell as described in claim 1, characterized in that, The 1064nm laser cell consists of at least one sub-cell, and the base region and emission region of each sub-cell are made of GaInAs.

4. The laser photovoltaic cell as described in claim 1, characterized in that, The component step-change buffer layer is AlGaInAs, and the band gap of AlGaInAs is larger than the band gap of the base region and the emitter region of the neutron cell in a 1064nm laser cell.

5. The laser photovoltaic cell as described in claim 4, characterized in that, Along the direction from the 808nm laser cell to the 1064nm laser cell, the step-change buffer layer is sequentially composed of step-change buffer layer 1, step-change buffer layer 2... step-change buffer layer (N-1), overshoot layer, and step-change buffer layer N; let the lattice constants of the base regions of the 808nm laser cell and the 1064nm laser cell be K and L, respectively, and the lattice constants of the step-change buffer layer 1, step-change buffer layer 2... step-change buffer layer (N-1), overshoot layer, and step-change buffer layer N be a1, a2, ..., a... n-1 b and a n Satisfying: K <a1<...<a2<a n-1 n ≤L <b。​ 6. The laser photovoltaic cell as described in claim 1, characterized in that, The supporting substrate is electroplated copper.

7. The laser photovoltaic cell as described in claim 2 or 3, characterized in that, Each sub-cell in the 808nm laser cell and the 1064nm laser cell independently includes a back field layer, a base region, an emission region, and a window layer, and the sub-cells are connected by tunnel junctions.

8. The laser photovoltaic cell as described in claim 1, characterized in that, The second electrode is ring-shaped, and the 808nm laser cell is located on the central axis of the second electrode.

9. The laser photovoltaic cell as described in claim 8, characterized in that, The distance between the second electrode and the 808nm laser cell is a, where a satisfies: 10μm≤a≤200μm.

10. A method for manufacturing a laser photovoltaic cell as described in any one of claims 1-9, characterized in that, Includes the following steps: (1) First, an ohmic contact layer, a current spreading layer, an 808nm laser cell, an electrode contact layer, a composition step change buffer layer, a 1064nm laser cell, and a first buffer layer are sequentially grown on the surface of a GaAs substrate to obtain an epitaxial layer. (2) Then the epitaxial layer is transferred to the support substrate and the GaAs substrate is removed; a first electrode is disposed on the upper surface of the ohmic contact layer, a second electrode is disposed on the upper surface of the electrode contact layer, and a third electrode is disposed on the lower surface of the support substrate.

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