Blue Photoluminescence from ZnCdO Films Grown by Molecular Beam Epitaxy

Blue luminescence from textured ZnCdO films grown by molecular beam epitaxy was observed. The properties of ZnCdO films grown at various Zn/Cd partial pressures were studied by several techniques including X-ray diffraction, fluorescence (FL) microscopy and Auger electron spectroscopy. With increasing CdO content, the properties of ZnCdO films changed sharply at specific Zn/Cd partial pressures. Some of the films grown at approximately the threshold pressures showed blue luminescence at room temperature, with large Stokes shift leaving the absorption edge in the UV region. By FL microscopy, it was observed that the blue luminescent regions were nonuniformly distributed, suggesting composition fluctuation.