Influence of Zinc Sulfide Shell Structure on Hydrogen Sensing Properties of Zinc Oxide Nanorod-based Gas Sensor

[[abstract]]在本論文中的實驗，我們先在二氧化矽(SiO2)上利用旋轉塗佈(spin-coating)法沉積晶種層(seed layer)，接著以水熱法(hydrothermal method)生長氧化鋅奈米柱(ZnO nanorods)，製作成氧化鋅奈米柱感測器。 生長完氧化鋅奈米柱後，同樣使用水熱法以不同的時間參數在氧化鋅奈米柱的表面長上一層硫化鋅殼層(ZnS shell)，便完成了本論文中的氧化鋅/硫化鋅殼核結構的氫氣感測器。而從感測的結果可以看出在長上硫化鋅殼層後，增加了奈米柱的電阻，進而增加了感測器之感測性能。 我們也對奈米柱的各方面性能做了測試，包括場發射電子顯微鏡(FESEM)、光致發光(PL)、X-射線繞射分析儀(XRD)、穿透式電子顯微鏡(TEM)、化學分析電子光譜儀(ESCA)等的測試。結果表明經過再次的水熱法後，氧化鋅奈米柱的表面確實被硫化成硫化鋅殼層，並在結構方面有良好的結晶度。 由於本實驗流程具簡單、環保、低成本等特性，且在對氫氣感測在低溫條件下就能有顯著的感測效果，有望開發成為將來使用於監測工作環境的感測器，為作業人員的工作安全做把關。而本實驗之硫化鋅/氧化鋅殼核結構也可開發用於如太陽能電池、照明等用途，為目前相當有前景的材料。[[abstract]]In this thesis, we first grew the seed layer on the silica sensor by spin coating methods. Then, we used hydrothermal methods to deposit the zinc oxide nanorods on top of the seed layer to make the zinc oxide nanorod sensors. After the growth of ZnO nanorods was completed, a similar hydrothermal method was used to grow a zinc sulfide shell on the surface of zinc oxide nanorods with different parameters. Thus, the zinc oxide nanorod sensor with core/shell structure was fabricated. Based on the sensing results, it can be seen that the electric resistance was increased after the zinc sulfide coating was formed, thereby increasing the sensing capability of the sensor. In addition, we also performed various material characterizations on these nanostructures including field-emission scanning electron microscope (FESEM), photoluminescence (PL), X-ray diffraction (XRD), transmission electron microscopy (TEM),electron spectroscopy for chemical analysis (ESCA) and other tests. The results show that after the two-step hydrothermal methods, the surface of ZnO nanorods was sulfurized to become ZnS shell and had good crystallinity in the structure. Owing to the simple, environmentally-friendly and low-cost features of this experimental process, it is expected to develop into a sensor that can be used to monitor the hydrogen gas in working environments in the future. These zinc sulfide / zinc oxide core shell structures can also be developed for applications such as solar cells, lighting and other purposes.[[note]]碩