CN111725332A - A high-performance triple-junction gallium arsenide solar cell - Google Patents

Abstract

The invention discloses a high-performance triple-junction gallium arsenide solar cell, comprising a Ge substrate, on which a Ge bottom cell, a first tunnel junction, a GaInAs middle cell, and a second tunnel junction are epitaxially grown by using MOCVD technology. Through junction and GaInP top cell; wherein, a transient metal oxide TMO is deposited on the emitter region of the GaInP top cell to obtain a TMO window layer, the band gap of the TMO window layer is greater than 3.0eV, and the transient metal oxide It can form a good ohmic contact with the metal upper electrode of the GaInP top cell, and its refractive index can be adjusted in the range of 1.4‑2.0, which can effectively play the role of an anti-reflection film, and optimize the photoelectric properties of the transient metal oxide. , can improve the short-circuit current and photoelectric conversion efficiency of the battery, and can also simplify the structure of the battery, reduce the chip process step, and effectively reduce the cost.

Description

A high-performance triple-junction gallium arsenide solar cell

technical field

The invention relates to the technical field of solar cells, in particular to a high-performance triple-junction gallium arsenide solar cell.

Background technique

At present, triple-junction gallium arsenide has been widely used in space power systems due to its high photoelectric conversion efficiency and good radiation resistance. For GaAs solar cells, the band gap of traditional window layer materials is generally around 2.0 eV, which has obvious light absorption to blue light. Therefore, it is necessary to adopt new window layer materials or new device structures to improve the short-wave response of top cells. , to improve the current matching between the middle and top batteries, and further improve the overall performance of the battery.

The window layer of gallium arsenide solar cells usually adopts wide bandgap materials such as GaInP, AlGaInP, AlInP, AlCaAs, etc. to suppress the interface recombination and limit the reverse diffusion of charges (the window layer is located between the anti-reflection film and the emission layer). In order to improve the utilization of the spectrum by the battery, double-layer films such as Al ₂ O ₃ /TiO ₂ and ZnS/MgF ₂ are usually used as the anti-reflection film of the gallium arsenide solar cell. However, the above anti-reflection film still has a considerable distance from the ideal 100% transmission effect, and the cost is relatively high.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art, and propose a high-performance triple-junction gallium arsenide solar cell, which adopts a wide bandgap transient metal oxide as the window layer of the triple-junction gallium arsenide solar cell, Its good optoelectronic properties can replace traditional window layer materials based on compound semiconductors, and at the same time can effectively reduce the reflection of incident light.

In order to achieve the above purpose, the technical solution provided by the present invention is: a high-performance triple-junction gallium arsenide solar cell, comprising a Ge substrate, and using MOCVD technology to epitaxially grow a Ge bottom cell and a first tunnel on the Ge substrate. Through junction, GaInAs middle cell, second tunnel junction and GaInP top cell; wherein, transient metal oxide TMO is deposited on the emitter region of the GaInP top cell to obtain a TMO window layer, the forbidden band width of the TMO window layer More than 3.0eV, its transient metal oxide can form a good ohmic contact with the metal upper electrode of the GaInP top cell, and its refractive index can be adjusted in the range of 1.4-2.0, which can play the role of anti-reflection film, and through Optimizing the photoelectric properties of transient metal oxides can improve the short-circuit current and photoelectric conversion efficiency of batteries.

Further, the transient metal oxide is molybdenum oxide or tungsten oxide.

Further, the Ge bottom cell, the GaInAs middle cell and the GaInP top cell are lattice matched;

The GaInP top cell includes a P-type doped AlInP or AlGaInP back field layer, a P-type doped GaInP base region, an n-type doped GaInP emitter region, and a TMO window layer, which are sequentially stacked according to the layered structure; wherein, the P-type doped GaInP The thickness of the back field layer doped with AlInP or AlGaInP is 50-200 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the thickness of the P-type doped GaInP base region is 300-600 nm, and the doping concentration is 1×10 ¹⁶ -1×10 ¹⁷ cm ^-3 ; the thickness of the n-type doped GaInP emission region is 50-100 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the TMO window layer The thickness of 30-200nm;

The second tunnel junction includes an n-type GaInP layer and a p-type AlGaAs layer superimposed in a layered structure; wherein, the thickness of the n-type GaInP layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 ; the thickness of the p-type AlGaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 ;

The GaInAs medium cell includes a P-type doped AlGaAs back field layer, a P-type doped GaInAs base region, an n-type doped GaInP emitter region, and an n-type doped AlInP window layer, which are sequentially stacked according to the layered structure; wherein, the The thickness of the P-type doped AlGaAs back field layer is 500-200nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the thickness of the P-type doped GaInAs base region is 1um-2um, and the doping concentration is 1×10 ¹⁶ -1×10 ¹⁷ cm ^-3 ; the thickness of the n-type doped GaInP emission region is 50-200 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the n-type doping The thickness of the hetero AlInP window layer is 30-100 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ;

A distributed Bragg reflector DBR is arranged between the first tunnel junction and the GaInAs middle cell, and the DBR includes 10-20 cycles of n-type doped AlGaAs and n-type doped GaAs alternately grown in sequence; wherein, The thickness of the n-type doped AlGaAs and the n-type doped GaAs is 30-100 nm, and the n-type doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ;

The first tunneling junction includes an n-type GaAs layer and a p-type AlGaAs layer superimposed in a layered structure; wherein, the thickness of the n-type GaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 ; the thickness of the p-type AlGaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 .

Further, the GaInAs middle cell and the GaInP top cell are lattice matched, and the Ge bottom cell is lattice mismatched with the GaInAs middle cell and the GaInP top cell, and is connected through a graded buffer layer GB;

The GaInP top cell includes a P-type doped AlInP or AlGaInP back field layer, a P-type doped GaInP base region, an n-type doped GaInP emitter region, and a TMO window layer, which are sequentially stacked according to the layered structure; wherein, the P-type doped GaInP The thickness of the back field layer doped with AlInP or AlGaInP is 50-200 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the thickness of the P-type doped GaInP base region is 300-600 nm, and the doping concentration is 1×10 ¹⁶ -1×10 ¹⁷ cm ^-3 ; the thickness of the n-type doped GaInP emission region is 50-100 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the TMO window layer The thickness of 30-200nm;

The second tunnel junction includes an n-type GaInP layer and a p-type AlGaAs layer superimposed in a layered structure; wherein, the thickness of the n-type GaInP layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 ; the thickness of the p-type AlGaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 ;

The GaInAs medium cell includes a P-type doped AlGaAs back field layer, a P-type doped GaInAs base region, an n-type doped GaInP emitter region, and an n-type doped AlInP window layer, which are sequentially stacked according to the layered structure; wherein, the The thickness of the P-type doped AlGaAs back field layer is 500-200nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the thickness of the P-type doped GaInAs base region is 1um-2um, and the doping concentration is 1×10 ¹⁶ -1×10 ¹⁷ cm ^-3 ; the thickness of the n-type doped GaInP emission region is 50-200 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the n-type doping The thickness of the hetero AlInP window layer is 30-100 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ;

A distributed Bragg reflector DBR and a graded buffer layer GB are sequentially arranged between the first tunnel junction and the GaInAs middle cell; the DBR includes 10-20 cycles of n-type doped Al _y (Ga _x In _1-x ) _1-y As and n-type doped Ga _x In _1-x As; wherein, the thickness of the n-type doped AlGaAs and n-type doped GaAs is 30-100 nm, and the n-type doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 , y is 0.9-1.0, and x is 0.9-1.0; the GB includes a plurality of successively stacked Ga _x In _1-x As sub-cells, using In composition linearity A progressive and/or step-by-step approach connects a Ge bottom cell and a Ga _x In _1-x As sub-cell in series with x of 0.9-1.0;

The first tunneling junction includes an n-type GaAs layer and a p-type AlGaAs layer superimposed in a layered structure; wherein, the thickness of the n-type GaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 ; the thickness of the p-type AlGaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 .

Further, the forbidden band widths of the Ge bottom cell, the GaInAs middle cell and the GaInP top cell are 0.67eV, 1.3eV, and 1.8eV, respectively.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. The use of wide bandgap transient metal oxides with good conductivity can significantly reduce the absorption of incident light by the window layer.

2. The transient metal oxide can form a good ohmic contact with the metal electrode, which can reduce the epitaxial growth of the gallium arsenide cap layer in the traditional process, and avoid the cap layer corrosion process in the chip process.

3. The refractive index of the transient metal oxide can be changed in the range of 1.4-2.0 by adjusting the process parameters, which can effectively play the role of anti-reflection film.

4. By optimizing the photoelectric properties of the transient metal oxide window layer material, the short-circuit current and photoelectric conversion efficiency of the battery can be significantly improved, and the structure of the battery can also be simplified, the chip process pace can be reduced, and the cost can be effectively reduced.

Description of drawings

FIG. 1 is a schematic structural diagram of a triple-junction gallium arsenide solar cell with forward lattice matching in Example 1. FIG.

FIG. 2 is a schematic structural diagram of a triple-junction gallium arsenide solar cell with forward lattice mismatch in Example 2. FIG.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments.

Example 1

Referring to FIG. 1 , the forward lattice matched triple-junction gallium arsenide solar cell provided in this embodiment includes a Ge substrate. The Ge substrate is placed in a MOCVD operating chamber, and the growth temperature is set at 500° C. to 800° C. , on the substrate sequentially epitaxially grow Ge bottom cell (also referred to as Ge cell), first tunnel junction, GaInAs middle cell (also referred to as GaInAs cell), second tunnel junction and GaInP top cell (also referred to as GaInAs cell) GaInP cell for short), put the substrate after epitaxial growth into ion-assisted deposition (IAD) or magnetron sputtering (Sputter) and other equipment to deposit transient metal oxide (TMO) on the emitter area of GaInP top cell , obtain a TMO window layer, wherein, the transient metal oxide is molybdenum oxide or tungsten oxide, the forbidden band width of the TMO window layer is greater than 3.0eV, when molybdenum oxide, tungsten oxide, etc. of the same thickness are used as the window layer at a wavelength of 400nm The light absorption is not more than 1%, which can effectively improve the quantum effect of the battery at 400nm-550nm. In addition, the transient metal oxide can form a good ohmic contact with the metal upper electrode of the GaInP top battery, and its refractive index passes through 1.4- The adjustment within the range of 2.0 can play the role of an anti-reflection film, and by optimizing the photoelectric properties of the transient metal oxide window layer material, the short-circuit current and photoelectric conversion efficiency of the battery can be significantly improved, and the battery can also be simplified. Structure, reduce chip process steps, effectively reduce costs.

The Ge bottom cell, GaInAs middle cell and GaInP top cell are lattice matched.

The GaInP top cell includes a P-type doped AlInP or AlGaInP back field layer, a P-type doped GaInP base region, an n-type doped GaInP emitter region, and a TMO window layer, which are sequentially stacked according to the layered structure; wherein, the P-type doped GaInP The thickness of the back field layer doped with AlInP or AlGaInP is 50-200 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the thickness of the P-type doped GaInP base region is 300-600 nm, and the doping concentration is 1×10 ¹⁶ -1×10 ¹⁷ cm ^-3 ; the thickness of the n-type doped GaInP emission region is 50-100 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the TMO window layer The thickness of 30-200nm.

The second tunnel junction includes an n-type GaInP layer and a p-type AlGaAs layer superimposed in a layered structure; wherein, the thickness of the n-type GaInP layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 ; the thickness of the p-type AlGaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 .

The GaInAs medium cell includes a P-type doped AlGaAs back field layer, a P-type doped GaInAs base region, an n-type doped GaInP emitter region, and an n-type doped AlInP window layer, which are sequentially stacked according to the layered structure; wherein, the The thickness of the P-type doped AlGaAs back field layer is 500-200nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the thickness of the P-type doped GaInAs base region is 1um-2um, and the doping concentration is 1×10 ¹⁶ -1×10 ¹⁷ cm ^-3 ; the thickness of the n-type doped GaInP emission region is 50-200 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the n-type doping The thickness of the hetero-AlInP window layer is 30-100 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 .

A distributed Bragg reflector (DBR) is arranged between the first tunnel junction and the GaInAs middle cell, and the DBR includes 10-20 cycles of n-type doped AlGaAs and n-type doped GaAs grown alternately in sequence; Wherein, the thickness of the n-type doped AlGaAs and the n-type doped GaAs is 30-100 nm, and the n-type doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 .

The first tunneling junction includes an n-type GaAs layer and a p-type AlGaAs layer superimposed in a layered structure; wherein, the thickness of the n-type GaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 ; the thickness of the p-type AlGaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 .

Example 2

Referring to FIG. 2 , the difference between the forward lattice mismatched triple-junction GaAs solar cell provided in this embodiment and Embodiment 1 is that the GaInAs middle cell and the GaInP top cell are lattice matched, and the Ge bottom cell is lattice-matched. The cell is lattice mismatched with the GaInAs middle cell and the GaInP top cell, and is connected through a graded buffer layer (GB). The forbidden band widths of the Ge bottom cell, the GaInAs middle cell and the GaInP top cell are preferably 0.67eV, 1.3eV, and 1.8eV; A distributed Bragg reflector (DBR) and a graded buffer layer (GB) are arranged between the first tunnel junction and the GaInAs middle cell in sequence; the DBR includes 10-20 cycles of n-type doping that alternately grow in sequence Aly(GaxIn1 _{-x ) 1-} yAs and n-type doped _{GaxIn1 - xAs} ; wherein, the thickness of the n-type doped AlGaAs and n-type doped GaAs is 30-100nm, n The doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 , y is 0.9-1.0, and x is 0.9-1.0; the GB includes a plurality of Ga _x In _1-x As sub-cells stacked in sequence, using The In composition linearly progressive and/or stepped approach connects the Ge bottom cell and the Ga _x In _1-x As sub-cell in series with x ranging from 0.9 to 1.0.

The above-mentioned embodiments are only preferred embodiments of the present invention, and are not intended to limit the scope of implementation of the present invention. Therefore, any changes made according to the shape and principle of the present invention should be included within the protection scope of the present invention.

Claims (5)

1. A high-performance triple-junction gallium arsenide solar cell, comprising a Ge substrate, and using MOCVD technology to epitaxially grow a Ge bottom cell, a first tunnel junction, a GaInAs middle cell, and a second tunnel junction on the Ge substrate and a GaInP top cell; it is characterized in that: a transient metal oxide TMO is deposited on the emitter region of the GaInP top cell to obtain a TMO window layer, the band gap of the TMO window layer is greater than 3.0eV, and the transient metal oxide It can form a good ohmic contact with the metal upper electrode of the GaInP top cell, and its refractive index can be adjusted by changing in the range of 1.4-2.0, which can play the role of an anti-reflection film, and by optimizing the photoelectric properties of the transient metal oxide, The short-circuit current and photoelectric conversion efficiency of the battery can be improved. 2 . The high-performance triple-junction gallium arsenide solar cell according to claim 1 , wherein the transient metal oxide is molybdenum oxide or tungsten oxide. 3 . 3. A high-performance triple-junction gallium arsenide solar cell according to claim 1, wherein the Ge bottom cell, the GaInAs middle cell and the GaInP top cell are lattice matched; The GaInP top cell includes a P-type doped AlInP or AlGaInP back field layer, a P-type doped GaInP base region, an n-type doped GaInP emitter region, and a TMO window layer, which are sequentially stacked according to the layered structure; wherein, the P-type doped GaInP The thickness of the back field layer doped with AlInP or AlGaInP is 50-200 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the thickness of the P-type doped GaInP base region is 300-600 nm, and the doping concentration is 1×10 ¹⁶ -1×10 ¹⁷ cm ^-3 ; the thickness of the n-type doped GaInP emission region is 50-100 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the TMO window layer The thickness of 30-200nm; The second tunnel junction includes an n-type GaInP layer and a p-type AlGaAs layer superimposed in a layered structure; wherein, the thickness of the n-type GaInP layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 ; the thickness of the p-type AlGaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 ; The GaInAs medium cell includes a P-type doped AlGaAs back field layer, a P-type doped GaInAs base region, an n-type doped GaInP emitter region, and an n-type doped AlInP window layer, which are sequentially stacked according to the layered structure; wherein, the The thickness of the P-type doped AlGaAs back field layer is 500-200nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the thickness of the P-type doped GaInAs base region is 1um-2um, and the doping concentration is 1×10 ¹⁶ -1×10 ¹⁷ cm ^-3 ; the thickness of the n-type doped GaInP emission region is 50-200 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the n-type doping The thickness of the hetero AlInP window layer is 30-100 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; A distributed Bragg reflector DBR is arranged between the first tunnel junction and the GaInAs middle cell, and the DBR includes 10-20 cycles of n-type doped AlGaAs and n-type doped GaAs alternately grown in sequence; wherein, The thickness of the n-type doped AlGaAs and the n-type doped GaAs is 30-100 nm, and the n-type doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; The first tunneling junction includes an n-type GaAs layer and a p-type AlGaAs layer superimposed in a layered structure; wherein, the thickness of the n-type GaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 ; the thickness of the p-type AlGaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 . 4. A high-performance triple-junction GaAs solar cell according to claim 1, wherein the GaInAs middle cell is lattice matched with the GaInP top cell, and the Ge bottom cell is matched with the GaInAs middle cell and the GaInP top cell. The cell lattice is mismatched and connected through the graded buffer layer GB; The GaInP top cell includes a P-type doped AlInP or AlGaInP back field layer, a P-type doped GaInP base region, an n-type doped GaInP emitter region, and a TMO window layer, which are sequentially stacked according to the layered structure; wherein, the P-type doped GaInP The thickness of the back field layer doped with AlInP or AlGaInP is 50-200 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the thickness of the P-type doped GaInP base region is 300-600 nm, and the doping concentration is 1×10 ¹⁶ -1×10 ¹⁷ cm ^-3 ; the thickness of the n-type doped GaInP emission region is 50-100 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the TMO window layer The thickness of 30-200nm; The second tunnel junction includes an n-type GaInP layer and a p-type AlGaAs layer superimposed in a layered structure; wherein, the thickness of the n-type GaInP layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 ; the thickness of the p-type AlGaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 ; The GaInAs medium cell includes a P-type doped AlGaAs back field layer, a P-type doped GaInAs base region, an n-type doped GaInP emitter region, and an n-type doped AlInP window layer, which are sequentially stacked according to the layered structure; wherein, the The thickness of the P-type doped AlGaAs back field layer is 500-200nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the thickness of the P-type doped GaInAs base region is 1um-2um, and the doping concentration is 1×10 ¹⁶ -1×10 ¹⁷ cm ^-3 ; the thickness of the n-type doped GaInP emission region is 50-200 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; the n-type doping The thickness of the hetero AlInP window layer is 30-100 nm, and the doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 ; A distributed Bragg reflector DBR and a graded buffer layer GB are sequentially arranged between the first tunnel junction and the GaInAs middle cell; the DBR includes 10-20 cycles of n-type doped Al _y (Ga _x In _1-x ) _1-y As and n-type doped Ga _x In _1-x As; wherein, the thickness of the n-type doped AlGaAs and n-type doped GaAs is 30-100 nm, and the n-type doping concentration is 1×10 ¹⁷ -1×10 ¹⁹ cm ^-3 , y is 0.9-1.0, and x is 0.9-1.0; the GB includes a plurality of successively stacked Ga _x In _1-x As sub-cells, using In composition linearity A progressive and/or step-by-step approach connects a Ge bottom cell and a Ga _x In _1-x As sub-cell in series with x of 0.9-1.0; The first tunneling junction includes an n-type GaAs layer and a p-type AlGaAs layer superimposed in a layered structure; wherein, the thickness of the n-type GaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 ; the thickness of the p-type AlGaAs layer is 5-30 nm, and the doping concentration is 1×10 ¹⁸ -1×10 ²⁰ cm ^-3 . 5. A high-performance triple-junction GaAs solar cell according to claim 4, wherein the band gaps of the Ge bottom cell, the GaInAs middle cell and the GaInP top cell are respectively 0.67eV, 1.3eV, 1.8eV.

Images