Investigation of InGaAsP solar cells grown by solid-state molecular beam epitaxy

• InGaAsP solar cells grown by molecular beam epitaxy is investigated.
• A high solar cell performance is obtained at a relatively high growth temperature.
• Higher growth temperature leads to longer minority carrier lifetime in InGaAsP.
• The influence of growth temperature is attributed to miscibility gap in InGaAsP.
• InP is more promising as the back surface field layer compared with InAlAs.

We report on the study of InGaAsP solar cells grown by solid-state molecular beam epitaxy (MBE) on InP. The effect of growth temperature on device performance is investigated. Under standard one-sun air-mass 1.5 global (AM1.5) illumination, an efficiency of 18.8% has been obtained for In0.78Ga0.22As0.48P0.52 single-junction solar cells grown at high temperature. Time-resolved photoluminescence (PL) results demonstrate that the In0.78Ga0.22As0.48P0.52 optical quality is greatly improved in the case of a high growth temperature. A longer PL decay time of In0.78Ga0.22As0.48P0.52/InP in contrast to In0.78Ga0.22As0.48P0.52/In0.52Al0.48As indicates that InP is more promising as the back surface field for future solar cell performance improvements.