Band alignment of lattice-mismatched In0.82Ga0.18As/InP heterojunction determined by x-ray photoemission spectroscopy

X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy were used to measure the band structure for high lattice-mismatched In0.82Ga0.18As/InP. The valence band offset was determined to be 0.43 eV, which is in agreement with the theoretical values based on the previous analysis. Together with a conduction band offset of 0.44 eV, it is indicated that a type-I band structure forms at the In0.82Ga0.18As/InP heterojunction. The precise determination of the band structure of In0.82Ga0.18As/InP is crucial for future device design and performance improvement. Besides, the valence band offset of In0.82Ga0.18As/GaAs was estimated to be 0.24 eV, which also presents a type-I band alignment.