Strain effects on indium incorporation and optical transitions in green-light InGaN heterostructures of different orientations

Strain effect on indium incorporation and optical transitions in bulk InGaN and GaN/InGaN/GaN quantum wells (QWs) coherently grown on GaN substrates with different orientations of hexagonal axis is studied by simulation. The strain modification in the nonpolar and semipolar structures, as compared to polar ones, is found to result in both a higher indium percentage in the InGaN alloy and a larger materials bandgap, producing opposite trends in variation of the optical transition energy (emission wavelength) with the crystal orientation. The interplay between the effects is discussed in view of development of green-light emitters. A possible way for controlling the strain in the InGaN layers and QWs and thus the emission wavelength is considered and tested by modelling. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim