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.
High efficiencies over 17.49% can be achieved on fabric platform. Fabric-based GaAs solar cells present the stable output power with high flexibility. GaAs photovoltaic (PV) cells have been extensively studied for flexible energy harvesting devices due to their merits such as thin-film feasibility, flexibility, and high-efficiency.
Recent advances have been made since 2017 by Alta Devices, where their flexible solar cells exceed efficiencies of 30%, aerial densities of 170 /, and are 30 thick. Their solar cells are widely used for aerospace purposes . Microlink Devices Inc. also supplies solar cells to the UAV sector.
The single-junction GaAs thin-film solar cell on a flexible substrate is made using the standard solar cell fabrication process. Figure 1 shows a cross-sectional scanning electron microscopy (SEM) image, obtained using focused ion beam (FIB) milling, of the fabricated GaAs thin-film solar cell on a flexible substrate.
There has been much interest in developing a thin-film solar cell because it is lightweight and flexible. The GaAs thin-film solar cell is a top contender in the thin-film solar cell market in that it has a high power conversion efficiency (PCE) compared to that of other thin-film solar cells.
The contact resistivity measured by a transmission line model (TLM) method 13 is 4 × 10 −4 Ω·cm 2. It is worth mentioning that the estimated PCE of 22.08% is much higher than that of the p-on-n solar cell fabricated on a flexible substrate 10. Figure 3: J−V curve of the GaAs thin-film solar cell with a conversion efficiency of 22.08%.