Development and optimization of a 1 eV (GaIn)(NAs) solar cell

(GaIn)(NAs) lattice matched to GaAs and Ge and having a 1 eV bandgap is a promising candidate for future space and terrestrial multi-junction solar cell structures. The present paper summarizes results of structural and optical characteristics of this metastable material system. It is shown, that photoluminescence (PL) intensity can be taken as a measure of improving minority carrier characteristics in solar cell devices. A direct correlation between PL intensity and quantum efficiency in the (GaIn)(NAs) material system is observed. Thermal annealing in this material can be used to initiate the site change of the Nitrogen atom from a Ga-rich environment upon growth to an In-rich one after annealing. In addition, the dissolution of chain-like N-ordering in [001] direction is detected. The greatly enhanced optical performance leads to an improved quantum efficiencies of the (GaIn)(NAs) solar cell material.