Schottky barrier height and interfacial state density on oxide-GaAs interface

Photoreflectance (PR) and Raman spectra were employed to investigate the interfacial characteristics of a series of oxide films on GaAs. The barrier heights across the interfaces and the densities of interfacial states are determined from the PR intensity as a function of the pump power density. The oxide-GaAs structures fabricated by in situ molecular beam epitaxy exhibit low interfacial state densities in the low 1011 cm−2 range. The density of the interface states of the Ga2O3(Gd2O3)–GaAs structure is as low as (1.24±0.14)×1010 cm−2. The Ga2O3(Gd2O3) dielectric film has effectively passivated the GaAs surface. Additionally, Raman spectra were used to characterize the structural properties of the oxide films.