TEMPERATURE-DEPENDENT PSEUDODIELECTRIC FUNCTIONS OF GAAS DETERMINED BY SPECTROSCOPIC ELLIPSOMETRY

We present the pseudodielectric functions of GaAs in the temperature range between 30 and 650°C. Data in the spectral range of 1.24<E<5.00 eV was obtained by spectroscopic ellipsometry in a molecular beam epitaxy system specially designed for this purpose. All measurements were performed in situ to avoid the presence of surface adsorbates, oxides, roughness and to ensure a group V stabilized surface is maintained. A simple two-phase model could thus be used to extract the dielectric functions. Temperature dependence of the critical point energies E1, E1+Δ1, E 0' and E2 are also determined. © 1995 American Institute of Physics.