Direct imaging of phase separation in ZnCdO layers

A direct correlation of structural and optical properties of MOCVD-grown ZnCdO-layers with a systematic variation of Cd-content has been achieved on a microscopic scale using highly spatially and spectrally resolved cathodoluminescence. The ZnCdO layer luminescence measured in cathodoluminescence wavelength images reveals strong lateral fluctuations directly visualizing local band gap fluctuation as a consequence of different local Cd incorporation. We give direct evidence for a chemical phase separation into Cd-rich and Cd-poor nanodomains in ZnCdO.