Preparation And Properties Of ZnO Thin Films

ZnO thin films are the materials with many excellent properties such as piezoelectricity, conductivity, optical absorption and emission, gas-sensitivity,and highly nolinear voltage-current characteristics. They have a wide variety of applications such as transparent conductors, luminescence diode, window materials for solar cells, optical wave guides, phosphor for monochrome field emission displays, piezoelectric transducers in the GHz range, surface acoustic wave devices, micro-sensors and micro-actuators, and low-voltage varistors.There are many methods for the preparation of ZnO thin films, and each has its advantages and disadvantages. The properties of ZnO thin films depend on the dopants and the preparating conditions. This paper reviews the prepartion and properties of ZnO thin films by two different methods: One is that Zn film was first prepared by ion beam sputtering and then annealed in O₂. Another is that ZnO was prepared by RF magnetron sputtering . The structures , morphologies , and electrical resistivities of the ZnO films prepared by two methods were investigated and compared.In chapter 1, we briefly review crystalline structure, all kinds of preparating methods , properties , the potential applications and progress about ZnO thin films .In chapter 2 we studied the preparations of ZnO thin films by RF magnetron sputtering and ion beam sputtering . The major content included the theory of RF magnetron sputtering and ion beam sputtering, processing of ZnO thin films preparations by RF sputtering and ion beam sputtering.In chapter 3, we discussed the influence factors including sputtering time and annealing treatment on structures and morphologies of ZnO films.The results indicated that the structure and roughness average of these samples were impoved with the sputtering time added, annealing treatment also improved the structure and roughness average.In chapter 4 , We also studied the influence including the sputtering time , differern substrates, ion beam sputtering and second sputtering , annealing temperature, heating time on structure , morphologies, electric properties of ZnO thin films by ion beam sputtering. The structure and roughness average of films were improved with sputtering time and heating time added. The structure and morphologies of films treated by ion sputtering and second sputtering variated . Through second sputtering treatment ,the particles size turned great and roughness average descended. Differernt substrates had different influence on structuer and morophologies of films.In chappter 5, ZnO films were prepared by IBD(ion beamsputtering depostion)and RF magnetron sputtering. Comparea with RF magnetron method , ZnO films prepared by IBD had a littery growth oriention ,its average surface roughness average is bigger and its electrical resistivity is higher too.