New technique for obtaining the electroreflectance spectrum: vacuum electroreflectance (Poster Paper)

Vacuum electroreflectance (VER), a new method for performing electroreflectance on a free standing surface, is introduced. In VER, the surface of the sample is in vacuum and does not come in contact with a dielectric or a metal. The sample is interferometrically aligned, and precise positioning is obtained by piezoelectric motors. Cooling to 80 K is accomplished by the Joule-Thompson effect, and temperatures up to 400 K are achieved by resistive heating. Comparison of data obtained at room temperature by VER, photoreflectance (PR), and electrolyte electroreflectance (EER), and at low temperature by VER ad PR on the same GaAs sample is presented. Also, the VER data is compared to the data obtained in air by the newly introduced contactless electroreflectance (CER) technique.