Zinc oxide is an inorganic compound also known as zincite and occurs rarely in nature, generally in a crystalline form. It is usually orange or red in color due to presence of manganese impurity. It usually appears as a white crystalline powder, which is nearly insoluble in water. Most of ZnO which is used commercially is produced synthetically. ZnO is actually a wide bandgap semiconductor of the II-VI semiconductor group. The doping of the semiconductor is n-type which is due to oxygen vacancies. This has several favorable properties like high electronmobility, good transparency, wide bandgap for seni-conductivity, high room-temperature luminescence, etc. These properties are used in applications for electrodes in liquid crystal displays aswell as in energy saving and heat protectingwindows, electronic applications of ZnO as thin-film transistors and light emitting diodes. Because of its unique properties and versatile applications, it is used in transparent electronics, ultraviolet light emitters, piezoelectric devices and chemical sensors.