Temperature dependence of optical properties of h-GaN films studied by reflectivity and ellipsometry
Spectroscopic ellipsometry (SE) carried out at 300 K together with reflectivity measurements performed from 5 to 300 K are used to determine the temperature dependence of the refractive index of hexagonal GaN films between 360 and 600 nm. The refractive index is well described with a Sellmeier dispersion law and its variation with temperature is given. Below the band gap, the three excitonic features (labelled A, B and C) appearing in the reflectivity spectra are analysed within a multi-polariton model which includes the spatial dispersion. The transition energy, broadening parameter and oscillator strength are derived. The temperature dependence of A and B broadening parameters is analysed.
Keywords: hexagonal GaN ; refractive index ; excitons ; temperature dependence ; ellipsometry ; reflectivity ; CHEMICAL-VAPOR-DEPOSITION ; ENERGY-GAP ; EPITAXIAL-FILMS ; HEXAGONAL GAN ; EXCITONS ; ABSORPTION ; SEMICONDUCTORS ; TRANSITIONS ; SAPPHIRE ; SPECTRA
Record created on 2010-10-05, modified on 2016-08-08