Overview of the Current State of Gallium Arsenide-Based Solar Cells

Abstract

As widely-available silicon solar cells, the development of GaAs-based solar cells has been ongoing for many years. Although cells on the gallium arsenide basis today achieve the highest efficiency of all, they are not very widespread. They have particular specifications that make them attractive, especially for certain areas. Thanks to their durability under challenging conditions, it is possible to operate them in places where other solar cells have already undergone significant degradation. This review summarizes past, present, and future uses of GaAs photovoltaic cells. It examines advances in their development, performance, and various current implementations and modifications.

Keywords: application; concentrators; degradation; gallium arsenide; solar cells; space; structure; uav.

Figure 1

(A) Stacks of discrete holographic elements (a single stack is described in part (C)) generate four spectral bands coupled into one of four dual-junction solar cells, including GaAs. Part (B) shows the volume phase hologram of thickness d with fringes representing the refractive index with periodicity L, tilted to the grating normal by angle ϕ, where incident light is split into diffracted orders $S_{\mathrm{i}}$ [9].

Figure 2

Airbus Zephyr during flight [34].

Figure 3

Prepared UAV PHASA-35 in hangar built by Prismatic for BAE Systems [43].

Figure 4

Fresnel lens concentrator focusing the light into one point without SOE [50].

Figure 5

FLATCON^® CPV module with 52 four-junction solar cells [51].

Figure 6

Parabolic mirror concentrator without optical lenses [50].

Figure 7

The basic construction of LSC with solar cell located on one side [50].

Figure 8

Image of the Ingenuity helicopter on Mars acquired on 7 April 2021 (Sol 46). IMM multi-junction solar cells are clearly visible from its top [64].

Figure 9

The differences (a) before and (b) after thermal processing of the cell scanned by an atomic force microscope (AFM) are considerable. The surface structure is entirely different. The average height of the feature on the surface changed from 7.16 nm to 15.73 nm after thermal heating [70,76].

Figure 10

The figure shows the reflectance before and after irradiation, divided into three groups—the ultraviolet spectrum, the visible region, and the near-infrared region. No significant changes are observed in the first two sections mentioned. Noteworthy is the last near-infrared region, where interference fringers give us information about changes in the thickness of the top layers [72].

Figure 11

(a) Light I–V curves and recalculated (b) power characteristics of GaAs specimen under supercontinuum laser processing. Maximum power points (MPPs) are marked. On day 42, efficiency improvements can be seen [73].

Figure 12

The images show cross-sectional view of the GaAs PV cell on a SEM microscope. The image (a) shows the complete structure of the PV cell. Contacts are visible from below and from top (contact is longitudinal along the edge). The largest part of the picture is occupied by germanium. However, the most important are the thin layers (the darkest part). The image (b) on the right represents the part marked with a yellow rectangle in image (a). The colored EBIC method (b) is used to visualize the distribution of carriers in the pn junction area. There is also applied bias voltage of −1 mV. Impurity (pointed by arrow), which was probably contaminated during the fabrication, is electrically active and allows easier tunneling of electrons through the junction [74].