Temperature dependence of the fundamental band gap parameters in cadmium-rich Zne?‘￥Cd1-e?‘￥Se using photoluminescence spectroscopy

摘要

Thin ???lms of ternary Zne?‘￥Cd1-e?‘￥Se were deposited on GaAs (100) substrate using metal-organic-chemical-vapour-deposition (MOCVD) technique. Temperature dependence of the near-band-edge emission from these Cd-rich Zne?‘￥ Cd1-e?‘￥Se (for e?‘￥ = 0.025, 0.045) ???lms has been studied using photoluminescence spectroscopy. Relevant parameters that describe temperature variation of the energy and broadening of the fundamental band gap have been evaluated using various models including the two-oscillator model, the Bosea€“Einstein model and the Varshni model. While all these models suf???ce to explain spectra at higher temperatures, the two-oscillator model not only explains low temperature spectra adequately but also provides additional information concerning phonon dispersion in these materials.