Research Of Micro-PL Of ZnO Single Crystal And Characteristics Simulation Of ZnO-based SAW Sensor

Zinc oxide is a kind of semiconductor with direct band gap and short light emission. It has a crystal structure and band structure similar as GaN. Its exciton energy(60 meV at room temperature) is much larger than that of GaN, which is helpful for the realization of electric-pumped light-emitting at room temperature. ZnO has a wide application prospect in the solid state lighting and laser devices. Furthermore, due to its high transmisivity, high conductivity and high electromechanical coupling coefficient, ZnO is appropriate for the fabrication of transparent field effect transistor, surface acoustic wave devices, transducers and solar energy battery. ZnO single crystal not only has good optical property, it also has excellent piezoelectricity property. Its electromechanical coupling coefficient is 0.816% and its phase velocity is 2683.9m/s approximately. Thus ZnO single crystal has a large advantage to be used in the fabrication of surface acoustic wave devices.In this paper, the photoelectronic properties of ZnO single crystal are introduced firstly. The XRD spectrum indicates a high level of crystallinity, crystal structure and photoluminescence properties are studied by the Raman spectrum, its luminescenceis generated by the transition between the electron in the conduction band and the hole in the valence band accompanied with combined action of exciton. The character of photoluminescence is different at different temperature,which is more obvious with the reduction of temperature from 300 K to 50 K. The intensity of the luminescence summit reveals stronger while the band reveals smaller. Experiment X-ray diffraction and photoluminescence which provides theoretical basis for the design and fabrication of single crystal ZnO-based devices. Secondly, the structure, working principle and performance of the SAW sensor are introduced, ZnO single crystal is used as piezoelectric substrate in the paper and the design and simulation of the SAW device is carried out by using the Comsol software in three dimensions.