We have performed contactless electroreflectance studies of the interband excitonic transitions of GaN thin films in the temperature range between 15 and 475 K. The parameters that describe the temperature dependence of the interband transition energies and the broadening function, ⌫(T), of the excitonic features are evaluated. The exciton-longitudinal optical phonon coupling constant, which is determined from an analysis of ⌫(T), is considerably larger than that for a number of the cubic III-V semiconductors.

We have measured the temperature dependence of the spectral features in the vicinity of the direct gap E g d of Si-containing carbon nitride polycrystalline films in the temperature range between 20 and 500 K using piezoreflectance ͑PzR͒. From a detailed line-shape fit to the PzR spectra, the E g d and the broadening parameter of direct band-to-band transitions at various temperatures are determined. The temperature dependence of E g d are analyzed by the Varshni equation ͓Physica 34, 149 ͑1967͔͒ and an empirical expression proposed by O'Donnel and Chen ͓Appl. Phys. Lett. 58, 2924 ͑1991͔͒. The parameters that describe the temperature dependence of the energy gap of the material are evaluated and discussed. The broadening parameter is found to be insensitive to the temperature variation. ͓S0163-1829͑97͒01135-X͔

Piezoreflectance (PzR) and contactless electroreflectance (CER) measurements of an In0.86Ga0.14As0.3P0.7/InP quantum well heterostructure as a function of temperature in the range of 20–300 K have been carried out. A careful analysis of the PzR and CER spectra has led to the identification of various excitonic transitions, mnH(L), between the mth conduction band state and the nth heavy (light)-hole band state. The parameters that describe the temperature dependence of EmnH(L) are evaluated. A detailed study of the temperature variation of excitonic transition energies indicates that the main influence of temperature on quantized transitions is through the temperature dependence of the band gap of the constituent material in the well. The temperature dependence of the linewidth of 11H exciton is evaluated and compared with that of the bulk material.