On the main photoelectric characteristics of three-junction InGaP/InGaAs/Ge solar cells in a broad temperature range (-197 $\le T\le$ +85$^\circ$C)

This study is aimed at investigating the main photoelectric characteristics of three-cascade InGaP/InGaAs/Ge photoelectric converters in a broad temperature range (-197 $\le T\le$ +85$^\circ$C). On account of analysis of photosensitivity spectra and optical current–voltage characteristics, such temperature dependences as the open-circuit voltage ($V_{\operatorname{oc}}$), filling factor of the current–voltage characteristic (FF), and the photoelectric conversion efficiency of solar radiation are determined. Investigations are performed at illumination intensities corresponding to operation under concentrated radiation. Decreased temperatures facilitate the selection of samples with the minimal “parasitic” potential barriers. The influence of excitationtransfer processes from a cascade into a cascade is estimated by means of secondary luminescent radiation. The highest photoelectric conversion efficiency of 52% is measured at a concentration multiplicity of 100 “suns” and a temperature of -160$^\circ$C.