Advances in ZnO: manipulation of defects for enhancing their technological potentials

This review attempts to compile the physics and chemistry of defects in zinc oxide (ZnO), at both, the fundamental and application levels. The defects, either inherent ones or introduced externally, have broadened the ZnO material field in various directions. The ZnO material exhibits many defect-attributed properties leading to broad technological applications: electronic and optoelectronic devices, sensors, optical components, ceramic industry, biomedical, catalysis, lightening, etc. Considering the huge defect-dependent technological scopes, the ZnO material is constantly engineered for various defects, and corresponding functionalities are tailored with respect to particular applications. The functional properties of ZnO are strongly influenced by the defects, and as a result, the defect engineering of the ZnO materials has remained an important motivation in materials science and engineering in terms of localized defects, extended defects, impurities, and surface defects, etc. A detailed characterization of these defects seems to be an essential part of any research area. The correlations of the microstructural characteristics with electrical and optical properties of ZnO are then a natural step for further facilitating an efficient way toward advanced ZnO-based materials and devices. The present review is an effort to shed light on the defects of ZnO, properties, theoretical aspects, and corresponding applications.