Investigation of the unusual temperature dependence of InGaN/GaN quantum well photoluminescence over a range of emission energies

An analysis of photoluminescence (PL) spectra for a range of single and multiple InGaN/GaN quantum wells, as a function of temperature, is presented. The well-known anomalous 'S-shape' behaviour is observed for samples emitting over a very wide range of energies. We present an analysis of this range of data, supplemented by other published data, in terms of different types of recombination sites within the wells. A quantitative model, based on previous work, to fit the temperature dependence of the emission peak energy is developed and gives good fits over an extended temperature range. The fitting parameters obtained are discussed in the light of values obtained from the literature and the intense piezoelectric fields present in the samples. Furthermore, the linewidth dependence of the PL emission peak energy in the region of the 'S-shape' is also analysed.