Study Of ZnO And Mg_xZn_1-xO Thin Films Prepared By Sol-gel

ZnO is a direct wide band-gap II-VI semiconductor material. Traditionally, ZnO is used as surface acoustic wave devices (SAW), bulk acoustic devices (BAW), gas sensors, varistors, transparent electrodes, UV-detectors, and etc. In recent years, ZnO has gained more and more attention as a wide band semiconductor. Compared to other wildly studied wide band semiconductors. ZnO is promising: high-quality ZnO with very low defect densities can be synthesized at much lower temperature; ZnO can emits light with shorter wavelength than blue light emission from GaN; ZnO has higher excitonic binding energy promising strong photoluminescence from the bound excitonic emissions even at room temperature; by alloying with MgO, tuning of the band gap while keeping the ZnO hexagonal structure can be achieved by forming MgxZn1-xO. As we know, band gap tuning is important to produce efficient and lasting light emitting diodes (LED) and other electronic devices.In this paper, the various growth techniques of ZnO films and the progresses in the research of ZnO were reviewed. And then, ZnO thin films were synthesize on quartz and silicon substrates by sol-gel dip-coating and spin-coating. The properties of the films and the effects of growth parameters on the quality of ZnO films were studied using X-ray diffraction, optical absorption, photoluminescence techniques, etc.To modify the energy gap of the ZnO, Mg2+ was added in the sol-gel solution, and MgxZn1-xO films were prepared by the same method as that for ZnO films. The effects of Mg content (x), and the annealing parameters on the properties of MgxZn1-xO films were also investigated.