AlInN/GaN based multi quantum well structures – growth and optical properties

High indium content ([In>]25%) AlInN/GaN multi quantum well structures grown by metal organic vapor phase epitaxy were analyzed by X‐ray diffraction, X‐ray reflection, and photoluminescence measurements. The samples, which exhibit an excellent crystalline quality and smooth interfaces, are found to show broad luminescence below the GaN‐bandgap which shifts with increasing indium content to longer wavelength. At elevated indium content an additional broadening of the luminescence band has been observed. A comparison of the AlInN bandgap and the luminescence energies shows a pronounced stokes shift. XPS measurements reveal a staggered band lineup in Al1‐xInxN /GaN heterostructures with x > 0.25 is found. These findings indicate an indirect transition from the AlInN conduction to the GaN valence band as origin of the luminescence behavior. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)