Study of anti-reflective coatings Tа2O5 / SiO2 for improving the efficiency of modern solar cells for space applications

Solar cells based on AIIIBV materials in solar arrays are the main energy sources for most modern spacecraft. In spite of the fact that high characteristics have already been achieved, the work for improving solar cells is being continued due to the growth of energy consumption by spacecraft. One of the directions is decreasing solar radiation reflection by solar cell surface due to the deposition of antireflec- tion coating (ARC). In the article we show the results of the study of ARC (Ta2O5 / SiO2). We have presented the results of spectral and thickness calculations by special software of ARC on the triple junc- tion (InGaP / InGaAs / Ge) solar cell taking into account cell structure as well. We have performed the experiment of ARC on the glass-substrate to confirm the manufacturability of the process. ARC deposition has been made by electron-beam evaporation in vacuum. The results of investigation of spectral char- acteristics of samples obtained by a spectrophotometer confirm the uniformity of covering without relation to the sam- ple position in a machine. Spectral characteristic calculations for glass-substrate coincide with experimental data. The results of studying spectral characteristics of ARC on a solar cell demonstrate good correspondence with experimental data. The electric characteristics measured by the solar simulator (AM0) before and after the ARC cover- ing on the experimental samples show the increase of short-circuit current up to 122 mA and the rise of efficiency up to 7.5 %. We have demonstrated the results of scanning electron microscopic investigation of ARC on the different positions of solar cells.