Temperature‐resolved photoluminescence of nonpolar InGaN/GaN multiple quantum well heterostructures grown on LiAlO 2

Polarized photoluminescence (PL) of a series of m ‐plane InGaN/GaN multiple quantum well heterostructures ( x In = 5‐30%) was measured in a wide temperature range (T = 10‐580 K). A pronounced S‐shape behaviour of PL band position was observed for all samples which is an evidence of a high degree of localization of photogenerated carriers. From temperature dependences of the PL degree of polarization, the energy difference between the two highest valence subbands Δ E in InGaN was estimated to be increasing from ∼70 meV to ∼160 meV with rising indium content from 5% to 30%. The high‐temperature spectral difference between the polarized PL components was substantially lower than Δ E which is caused by imperfect polarization of optical transitions to different valence subbands. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)