On the temperature dependence of the InP(001) bulk and surface dielectric function

The bulk dielectric function and the surface dielectric anisotropy (SDA) of InP(001) were determined from room temperature up to 873 K. Measurements were performed on as-grown samples both in a metalorganic vapour phase epitaxy (MOVPE) and a chemical beam epitaxy (CBE) system using a rotating analyser type ellipsometer (SE) and a reflectance anisotropy spectrometer (RAS). The temperature dependence of the bulk critical points was deduced by performing a line shape analysis of the dielectric function in the framework of parabolic band approximation. The SDA spectra were obtained from combined RAS and SE measurements. Oscillator like structures in the SDA spectra are assigned to the dimer related transitions characteristic for the two dominating InP surface reconstructions: (2×1) and (2×4). These reconstructions were assigned to the RAS spectra by reflection high-energy electron diffraction (RHEED) measurements in the CBE system. The temperature dependence of the surface related transitions is found to be different to that of the bulk critical points