Materials aspects of multijunction solar cells

Abstract Atomic layer epitaxy (ALE) was used to grow several components of the cascade solar cell structure in the AlGaAs/GaAs system. An ALE reactor was constructed for multiwafer growth with a growth rate of 0.6 μm h −1 . Device quality GaAs and As x Ga 1−x As films were grown with p-type background carbon doping in the ranges 10 15 –10 19 cm −3 and 10 16 –10 20 cm −3 respectively. N-type films were achieved by SiH 4 doping, producing carrier concentrations in the range 10 16 –10 18 cm −3 . In addition, the potential applications of the ALE technique in the photovoltaic field are discussed.