We present the results of a comparative photoluminescence(PL) study of GaN and InGaN-based epilayers, and InGaN/GaN multiple quantum wells(MQWs). Room-temperature PL spectra were measured for a very broad range of optical excitation from 10 mW/cm2 up to 1 MW/cm2. In contrast to GaN epilayers, all In-containing samples exhibited an excitation-induced blueshift of the peak emission. In addition, the blueshift of the emission in the InGaN epilayers with the same composition as the quantum well was significantly smaller. The comparison of the blueshift in the “bulk” InGaN and in the MQWs allowed us to separate two different mechanisms responsible for this effect: (i) filling of the localized states in In-rich areas and (ii) screening of the polarizationelectric field in strained MQW structures.
Published in Applied Physics Letters, Volume 80, Issue 6, 2002, pages 977-979.
©Applied Physics Letters 2002, American Institute of Physics (AIP).
Kuokstis, E., Yang, J. W., Simin, G., Khan, M. A., Gaska, R., & Shur, M. S. (11 February 2002). Two Mechanisms of Blueshift of Edge Emission in InGaN-Based Epilayers and Multiple Quantum Wells. Applied Physics Letters, 80 (6), 977-979. http://dx.doi.org/10.1063/1.1433164