Abstract

We study the carrier localization in InN/In(0.9)Ga(0.1)AN multiple-quantum-wells (MQWs) and bulk InN by means of temperature-dependent photoluminescence and pump-probe measurements at 1.55 mu m. The S-shaped thermal evolution of the emission energy of the InN film is attributed to carrier localization at structural defects with an average localization energy of similar to 12 meV. Carrier localization is enhanced in the MQWs due to well/barrier thickness and ternary alloy composition fluctuations, leading to a localization energy above 35 meV and longer carrier relaxation time. As a result, the luminescence efficiency in the MQWs is improved by a factor of five over bulk InN. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4742157]