Photoreflectance characterization of built-in potential in MBE-produced As-grown GaAs surface

Photoreflectance (PR) spectroscopy has been used to study the built-in surface potential in GaAs epitaxial film grown by molecular beam epitaxy (MBE). The PR signal amplitude ILIR/RI sensitively depends on modulation light power, built-in surface potential and temperature. From the analysis of the modulation light power dependence of IzlR/RI, the built-in surface potential of 0.47±0.09eV was determined for a MBE-grown GaAs(lOO) epitaxial film, and the increase of the surface potential by gold deposition was observed.