Impact of local arrangement of Mg and Zn atoms in rocksalt-structured MgxZn1-xO alloys on bandgap and deep UV cathodoluminescence peak energies

Observation of deep ultraviolet (UV) cathodoluminescence peaks around 4.88-5.86 eV and optical transmittance measurements in the far UV spectral range enabled us to find a relatively large Stokes-like shift of 0.7-0.8 eV in rocksalt-structured (RS) MgxZn1-xO films with x = 0.61-0.92 grown on (001) MgO substrates by using the mist chemical vapor deposition method. Electronic structure calculations suggested the existence of bandgap energy (E-g) fluctuations induced by differences in the local arrangement of Mg and Zn atoms in the RS-MgxZn1-xO alloy. The E-g fluctuations and resultant exciton localization were determined to be possible origins of the large Stokes-like shift. Published by AIP Publishing.