First-principles study of electronic and optical properties in wurtzite Zn 1x Cd x O

ZnO has been used for a variety of applications, such asgas sensors, surface acoustic wave devices, biomedical ma-terials, and transparent contacts. Due to the direct band gapof 3.37 eV and the large binding energy of exciton, ZnO-based semiconductors are recognized as very promising pho-tonic materials in the ultraviolet and visible regions. A cru-cial step in designing modern optoelectronic devices is therealization of band gap engineering to create barrier layersand quantum wells in device heterostructures. In order torealize such optoelectronic devices, two crucial challengesare