Growth of device-quality GaAs layer directly on (001) Ge substrates by both solid-source and gas-source MBE

A detailed study of GaAs grown directly on offcut (001) Ge substrates by both solid-source and gas-source molecular beam epitaxy (MBE) has been conducted. It was found that control of As2 initial exposure and a clean Ge surface were crucial to achieve anti-phase domain-free growth of GaAs on Ge. Under optimized growth conditions device-quality GaAs film was obtained, in which significantly reduced interdiffusion across the GaAs/Ge interface was achieved.