| Summary: | 碩士 === 中國文化大學 === 材料科學與奈米科技研究所 === 98 === In this study, high-density ZnS nanowires and ZnS/ZnO core-shell nanowires were synthesized on Si and Al2O3 substrates using thermal evaporation at 1000 °C for 1 h in one-step.
In the ZnS nanowires, the results indicated that the ZnS nanowires had diameters of 20 to 50 nm and lengths of 5 to 15 μm by field emission scanning electron microscope (FE-SEM). The major diffraction planes of (002) and (110) for the ZnS nanowires in wurtzite structure and the major diffraction planes of (111) and (220) for the ZnS nanowires in zinc blende structure were examined by x-ray diffraction (XRD). The results of x-ray photoelectron spectroscopy (XPS) indicated that the major orbits of Zn and S were both of the 2p3. The wurtzite structure and the zinc blende structure were grown in the direction of [0002] and [111], respectively, by high-resolution transmission electron microscope (HR-TEM). The cathodoluminescence (CL) spectra showed that ZnS nanowires exhibited blue and green emission. The photo-sensing measurement demonstrated that the ZnS nanowire-based photodetectors had high sensitivity and high recovery time.
In the ZnS/ZnO core-shell nanowires, the results indicated that the ZnS-ZnO core-shell nanowires had diameters of 50 to 100 nm and lengths of 5 to 10 μm by FE-SEM. The major diffraction planes of (002) and (110) for the ZnS-ZnO core-shell nanowires were examined by XRD. The results of XPS indicated the major orbits of Zn, S and O were 2p3, 2p3 and 1s, respectively. Both of ZnS and ZnO are of single crystalline hexagonal wurtzite structure with the same growth direction of [0002] by HR-TEM. The CL spectra showed that ZnS/ZnO core-shell nanowires exhibited a green emission. The photo-sensing measurement demonstrated that the ZnS/ZnO core-shell nanowire-based photodetectors had low sensitivity and low recovery time.
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