The Technical Optimization And Study Of Optical Properties Of ZnO Thin Films Prepared By Sol-gel Technique

ZnO is a novel Ⅱ Ⅵ family compound, which is a wide direct-gap semiconductor. Its crystal lattice constant and bandgaps is analogical to GaN, which will have great uses in photoelectricity field by way of short wavelength devices. Therefore, ZnO thin film attracts much attention I n photoelectric research field.ZnO, AZO and Mg_xZn_1-xO thin films were prepared on Si (111) in the sol-gel process. Applying the theory of orthogonal-design, the technological conditions were optimized after investigation and analysis of the samples by XRD.The results revealed that, for preparing highly oriented along c-axis and optical property films, the optimized growing parameters at Si (111) substrate were:ZnO:0.35mol/l(Zn²⁺),50℃(aging temperature),300℃(preheating temperature),650℃ (annealing temperature) and two hours (heating time);AZO:1%(Al³⁺),50℃(aging temperature) ,200℃(preheating temperature),750℃ (annealing temperature)and two hours(heating time);Mg_xZn_1-xO:X=0.15,50℃(aging temperature),200℃(preheating temperature) ,550℃ (annealing temperature) and two hours (heating time);Photoluminescence spectra showed a better UV emission of 390nm of ZnO ,AZO films, but Mg_xZn_1-xO films had a bule-shift to 370nm. The surfaces morphology of ZnO, AZO and Mg_xZn_1-xO thin films showed well-proportioned hexagonal grains indicated by atomic force microscope (AFM) ,the grain sizes were 20⁶0nm.