Reduction of Point Defects and Formation of Abrupt Hetero-Interfaces in Low-Temperature Molecular Beam Epitaxy of GaAs and GaP under Atomic Hydrogen Irradiation

The removal effect of excess As and P atoms adsorbed on GaAs (100) and GaP (100) surfaces by atomic hydrogen (H) irradiation was investigated by reflection high-energy electron diffraction and X-ray photoelectron spectroscopy. It was found that the excess As and P atoms were effectively removed by atomic H irradiation at a low temperature of 350°C. Then, we attempted to obtain a high-quality GaAs epitaxial layer and an ordered (GaAs) 1 (GaP) 3 strained short-period superlattice (SSPS) with abrupt GaAs/GaP hetero-interfaces in the low-temperature growth under atomic H irradiation. The quality of the GaAs epitaxial layer and the abruptness of the GaAs/GaP hetero-interfaces in the (GaAs) 1 (GaP) 3 SSPS were evaluated by photoluminescence, deep-level transient spectroscopy and transmission electron microscopy. As a result, it was clarified that the density of point defects in the GaAs epitaxial layer was reduced and an abrupt GaAs/GaP hetero-interface of the (GaAs) 1 (GaP) 3 SSPS was formed in the low-temperature growth under atomic H irradiation.