Luminescent properties of GaN thin films prepared by pulsed laser deposition

The luminescent properties of GaN thin films grown by pulsed laser depositi on have been studied to understand the nature of the luminescent centres an d the recombination dynamics. The films were grown on heated sapphire subst rates using KrF excimer laser ablation of GaN in a reactive atmosphere of n itrogen. At low temperature the continuous wave (CW) blue luminescence of t he samples grown shows two sharp lines attributed to excitonic recombinatio n localized at extended defects. An analysis of the temperature dependence of photoluminescence (PL) lifetimes assesses the relative contributions of radiative and non-radiative recombination in the centres responsible for th ese emissions. The measurement of room temperature nanosecond radiative lif etimes for these lines supports the excitonic attribution of the luminescen ce. (C) 1999 Elsevier Science S.A. All rights reserved.