| The photoelectronic properties of semiconductor has been always the focus of scientific research. It has appeared many theoretical research papers, as well as many experimental researches, which have proved semiconductor oxide has potential applications in photoelectronic field. ZnO is a typical semiconductor oxide material. For its unique properties, it has applied in optical, photoelectronic, biological, medicine, catalysis, environment and so on. Because of the defects of itself limit its development. The current research on magic photoelectronic properties of metal nanostructure has appeared properties of semiconductor nanostructure can be improved by metal nanostructure modifing. This thesis studies metal modified ZnO based nanostructure, these structures applied on UV photoluminescence (PL), UV detection and H2O2electrochemical sensor. The results are as follows:(1) The study of PL properties of metal nanostructure modified ZnO nanoparticle (NP) film. The thickness of ZnO NP film can affect its PL property as well as the coupling effect of metal NP/ZnO surface plasma resonance (SPR). The result reveals PL intensity of Ti coated ZnO film (the thickness of267nm) enhanced about19times than uncoated ZnO film. While the PL intensity enhancement of Al coated ZnO only about5times. The difference of PL enhancement between Ti and Al metal can be explained as the coupling energy at Ti/ZnO interface much closer to band gap energy of ZnO than the energy of Al/ZnO. Because of incident light absorption increase, metal The PL intensity appears quenching with the thickness of metal increasing.(2) Inspired by the above results, we have studied the affection of ZnO NP film morphology on coupling intensity on metal/ZnO interface. The results reveal SPR energy of metal nanostructure depend on the ratio of metal nanopaticles space to its diameter (8/d).700℃annealed ZnO NP film provide a optimal substrate morphology for Ti metal, that is to say,700℃annealed film with the smallest ratio of8/d than films annealed at other temperature. These experimental results may give a feasible way to tune the coupling energy of metal and dielectric materials by controlling the surface structure of the dielectric.(3) ZnO-Ag heterosturcture nanofilm are prepared by spinning coating method. Morphology, structure characterization results of ZnO-Ag film appear Ag atoms gather become cluster. ZnO-silver (Ag) heterostructure nanoparticle films were prepared by spin-coating, followed by annealing at700℃for2h. The films were then used as UV photodetector which show high photoresponse. The heterostructure-film device displayed an ultrafast decay time of18ms and a rise time of50ms upon ultraviolet irradiation. Additionally, the time-dependent photocurrent upon UV switching reveals a rectangularly shaped profile, rarely reported in previous literature. The highly improved photoresponse properties of ZnO-Ag heterostructure-film device could be attributed to the Schottky barrier height (SBH) and depletion width reduction from the embedded Ag nanoclusters. Compared to a pure ZnO film, both the responsivity (Rλ) and external quantum efficiency (EQE) of the ZnO-Ag heterostructure-film photodetectors were improved more than13-fold. This research provides a promising strategy for fabricating UV-photodetectors with ultrafast response.(4) Composite nanotubes modified electrodes with enhanced photoelectrochemical (PEC) performance have great potentialities in biological systems monitoring and detection. In this paper ZnO-SnO2and SnO2nanotubes were prepared by electrospinning. The results show that visible light emission intensity of ZnO-SnO2composite nanotubes is much higher than that of SnO2nanotubes, indicating exsitence of large amount of oxygen defects in ZnO-SnO2nanotubes. Photocurrent response of SnO2nanotubes electrode to hydrogen peroxide (H2O2) randomly increases with increased H2O2concentration. While the dark current and photocurrent of ZnO-SnO2nanotubes electrode decrease exponentially and linearly, respectively. Moreover, ZnO-SnO2nanotubes electrode appears more outstanding H2O2sensing capability than pure SnO2nanotubes electrode under UV radiation. These can be well explained by electron transfer mechanism in ZnO-SnO2nano-composite. Different reactions on SnO2and ZnO-SnO2surface have been explained in details based on PEC performances of the two modified electrodes. This facile strategy extends the application of semiconductor composite for monitoring biomolecules with PEC method. Inspired by the above results, Pt NP coated ZnO nanorod arrays are prepared by hydrothermal method appling on H2O2electrochemical detection. The results show that Pt coated ZnO arrays possess faster response speed and wider detection range than ZnO arrays without Pt coating. |
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