Optical nonlinearity of ZnO microcrystallite enhanced by interfacial state.

A series of ZnO microcrystallite films deposited on quartz substrates were annealed at the temperature of 600~1050 masculineC. A well c-axis grown wurtzite ZnO film was obtained at the annealing temperature of 850 masculineC. For the samples annealed above this temperature, the empirical parameter E(0) increased calculated from transmittance spectra, which indicated the changes of the interface of ZnO microcrystallite. Measured by Z-scans, the nonlinear absorption coefficient beta(eff) increased from 1.2x10(2) cm/GW to 1.1x10(3) cm/GW when the annealing temperature rose from 950 masculineC to 1050 masculineC, mainly due to the interfacial state enhancement.