Temperature‐resolved photoluminescence of nonpolar InGaN/GaN multiple quantum well heterostructures grown on LiAlO2

Polarized photoluminescence (PL) of a series of m -plane InGaN/GaN multiple quantum well heterostructures (xIn = 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 ΔE 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 ΔE which is caused by imperfect polarization of optical transitions to different valence subbands. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)