Deep level related photoluminescence in ZnMgO

Optically active deep levels were investigated in ZnMgO layers using temperature dependent photoluminescence. The samples, grown on c-plane sapphire by metal-organic vapor phase epitaxy, exhibited Mg contents ranging from 0% to 8.5% leading to a gradual band gap broadening. The deep level luminescence was found to consist of several emission components centered at 2, 2.3, 2.5, 2.8, and 3 eV. With increasing Mg concentration, the bands at 2.8 and 3eV were found to blueshift, the bands at 2.3 and 2.5eV redshift, while the band at 2 eV holds its position. A model is suggested explaining the deep level luminescence shift trends in terms of interaction of native Zn and O sublattice defects with the introduced Mg interstitials. (C) 2010 American Institute of Physics. [doi:10.1063/1.3518480]