Thermal degradation of homoepitaxial GaAs interfaces

Photoluminescence techniques have been used to detect and characterize p-type conducting layers formed on the surface of semi-insulating GaAs substrates and at the liquid phase epitaxial layer–GaAs substrate interface during pregrowth heat treatment. These layers contain ∼1017 cm−3 shallow acceptors and a high density of arsenic vacancy complexes, and can be eliminated by pregrowth Ga etching of the substrate.