Optical and structural analysis of ZnCdO layers grown by metalorganic vapor-phase epitaxy

Abstract

The development of ZnO-based semiconductor devices requires band gap engineering. Ternary Zn1−xCdxO allows reduction of the band gap relative to ZnO, which would be necessary for devices emitting visible light. We have analyzed the structural and optical properties of Zn1−xCdxO layers grown by metalorganic vapor-phase epitaxy. A narrowing of the fundamental band gap of up to 300 meV has been observed, while introducing a lattice mismatch of only 0.5% with respect to binary ZnO. Photoluminescence, high-resolution x-ray diffraction, and spatially resolved cathodoluminescence measurements revealed a lateral distribution of two different cadmium concentrations within the Zn1−xCdxO layers.