| The morphology of ZnO nanowhiskers was demonstrated with obvious fractal characteristics, which play a role in determination of the properties. ZnO nanowhiskers synthesized by oxidizing Zn vapor at low pressure show different morphology in this study. According to fractal dimension theory, fractal dimension calculation program (FDCP) has been developed to calculate the fractal dimensions of ZnO nanowhiskers. On the basis of orthogonal test, the optimum procedure parameters were determined. It is evaporating temperature of 750 , reaction pressure of 4000pa and O2 content of 50%. The evaporating temperature and reaction pressure are key procedure parameters. The former is related with fractal dimension, as FD=-4E-05 T2+ 0.0647 T - 23.872 and the relation between reaction pressure and fractal dimension can be described by the function of FD=-5E-09 P2 + 6E-05 P + 1.5897. Also the fractal dimensions and BET surface area can be described by the function of y - Q.Ql82e3M72*. In the graph of their pore size distribution, pore size where pore volume is maximal becomes smaller and smaller with the increasing of fractal dimensions. The UV emission of ZnO nanoparticles can be attributed to the free exciton emission at 380nm. The intensity of UV emission is greatly influenced by crystal structure. The sample of WD3 which is optimum process decided by orthogonal test exhibits fine photoluminescence. The Photoluminescence was not found in the samples of YL1 and BL3 which are 2000pa of 50%O2 and 50%Ar , 4000pa of 60%O2 and 40% at temperature 800 because of impurities and vacancies which eliminate the excitons.
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