In this work, the carrier localization effect is studied in molecular beam epitaxy grown MgZnO epitaxial layers. The photoluminescence (PL) investigation revealed the S -shaped PL peak position dependence on temperature. It is usually related to the carrier localization in randomly distributed potential field fluctuations. We have measured double blue-shift of the PL peak position with increase of temperature for samples with higher (17–30%) Mg content in the alloys.
The two blue-shifts are attributed to double-scale potential field fluctuations with different average localization energy. The scanning near optical field microscopy experiment proved the presence of less than 100 nm width Mg rich areas with enhanced PL intensity. The atomic force microscopy and energy dispersive X-ray diffraction experiments revealed a close relation of structural and optical quality with the evaluated average carriers localization energy. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)