THE RENASCENCE OF ZnO - PROPERTIES AND APPLICATIONS

ZnO is a material widely Used in industry for decades, which experiences a scientific and technical renascence in the last few years. ZnO is a wide band gap semiconductor (3.37 eV at room temperature) with direct electronic transitions, a large exciton energy (60 meV) and hexagonal close-packed structure (wurtzite). Its Unique chemical, surface and nanoscale properties give opportunities to find different new applications of ZnO in optoelectronics, planar optical waveguides, bio-application etc. It also defines application of ZnO as a transparent conducting electrode for photovoltaics (solar cells) and light emitting diodes, and also as phosphorescent and luminescent material in the visible (blue-green) and Ultraviolet regions. Recently it attracted considerable attention for gas sensors and antibacterial applications, as it withstands harsh process conditions and is a material safe to human beings and animals. In this contribution the structural and optical properties of nanocrystalline ZnO films deposited by magnetron sputtering are presented and analysed in dependence of the deposition conditions and doping. The sensitivity of undoped and doped ZnO films to ammonia at room temperature is compared and discussed.