Synthesis And Characterization Of ZnO Thin Films

Recent years, semiconductor nanocrystle has wide application to immunization biologyand clinical examine, which gives rise to workers' interest. Zinc oxide (ZnO) is a wide bandgap (3.37 eV) semiconductor oxide and has a large exciton binding energy (60 meV), whichallows its high efficient ultraviolet (UV) emission from the exciton and wide application toshort-wavelength laser diodes and UV detectors. We fabricated a inorganic-polymeric photoluminescent thin film based on ZnOnanoparticles, which were grown directly in the poly(vinylpyrrolidone) (PVP) polymer matrix.The microstructure, thermal stability, and photoluminescence of the thin film wereinvestigated. Result: X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicatedthat all the ZnO nanoparticles were well separated from each other and were dispersed in thepolymeric matrix homogeneously and randomly with a polycrystalline hexagonal wurtzitestructure. Raman spectrum (Raman) showed a typical resonant multi-phonon process withinthe hybrid thin film. The shifts of infrared bands for PVP in the hybrid film should beattributed to strong coulombic interaction between ZnO and polymeric matrix. The stability ofthe hybrid film and the effect of the perturbation of ZnO on the stability were determined bymeans of the thermogravimetric analysis (TG) and differential thermal analysis (DTA). Theultraviolet-visible adsorption (UV-vis) showed distinct excitonic features. Thephotoluminescent spectrum (PL) of the ZnO nanoparticles modified by PVP moleculesshowed markedly enhanced ultraviolet emission and significantly reduced green emission,which was due to the pefect surface passivation of ZnO nanoparticles. Temperature dependentphotoluminescent spectrum studies suggested that the ultraviolet emission was associatedwith bound exciton recombination.