Improved Photoabsorption in Thin Gallium Arsenide Solar Cells using Light Trapping Techniques

Thin absorbers for space photovoltaics can achieve higher radiation tolerance, however, they suffer from reduced photoabsorption as the active region is thinned. In this work, increasing the photoabsorption in thin single junction n-i-p GaAs solar cells have been investigated by applying different light trapping structures at the rear of the cell. The main focus has been to develop a random surface texture that varies in three dimensions to increase light scattering and the effective optical path length. From the EQE, the random back surface reflector was successfully applied to a 1.1 μm thick GaAs solar cell which resulted in a notable 38% increase in current output, when compared to the GaAs baseline cell on its substrate without a BSR. The random texture has shown the capability to maintain the current output in the 1.1 μm thick GaAs absorber and shows promise for enhancing the photoabsorption in thin GaAs absorbers that approach the sub-μm thickness regime.