2.0–2.2 eV AlGaInP solar cells grown by molecular beam epitaxy

Abstract We demonstrate 2.0–2.2 eV AlGaInP solar cells grown by molecular beam epitaxy and their performance improvement by rapid thermal annealing (RTA). As grown, these cells exhibit lower performance than their counterparts grown by metal-organic vapor phase epitaxy (MOVPE), indicating a high concentration of point defects. RTA improves all aspects of performance, enabling our 2.0 eV cells to match the efficiency of MOVPE-grown cells. RTA also improves the performance of wider-bandgap AlGaInP solar cells, but the magnitude of improvement decreases with %Al/bandgap energy.