Dependence of carrier localization in InGaN/GaN multiple-quantum wells on well thickness

Carrier localization in InGaN/GaN multiple-quantum wells (MQWs) with three different well thicknesses was investigated optically using time-integrated and time-resolved microphotoluminescence spectroscopy. An anomalous temperature dependence of the photoluminescence peak energy was observed, as a consequence of local potential fluctuations. The carrier localization was more prominent in the case of MQWs with wide well thickness. The results indicate that the degree of potential fluctuation increases with increasing well thickness. Emission from quantum-dot-like states only became apparent in MQWs with wide well thickness, which supports the assertion that carrier localization in InGaN/GaN MQWs is due to the formation of quantum dots. (c) 2006 American Institute of Physics.