| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 100 === There are many technologies to fabricate one-dimensional silicon nanostructure.
The silicon nanostructures were used for many applications. For example, the silicon nanostructures have high reflection property in solar cell. In the electron field emission, the silicon nanostructures possess the higher aspect ratio and numerous emission sites. For sensor researching, it has higher surface area to volume ratio that can improve the sensitivity.
We fabricated the one dimension silicon nanostructure for hydrogen sensor. In this research, we synthesized different morphology of silicon nanostructure using wet electroless etching technique. The field emission scanning electron microscopy (FE-SEM) was used to observe the surface morphology of silicon nanostructure. The micro-Raman and Fourier transform infrared (FT-IR) was used to investigate the bonding of silicon nanostructure. Finally, we carried out the electrical analyze of gas sensor system with hydrogen sensing.
In this study, we use the two-step wet electroless etching technique to form the straw-like silicon nanowire. It can be observed that some different layers in SEM photographs. The top layer was straw-like silicon nanowire, and the middle layer was straight aligned silicon nanowire, and the bottom layer was silicon base which is the bulk silicon. The straw-like silicon nanowire was found the the bonding of Si-O-Si about 1173cm-1 in FT-IR spectrum. And it also observed some red shift in Raman spectrum. Because of the higher surface area to volume ratio and Si-O-Si bonding, the performance of this straw-like structure hydrogen sensor was improved. Moreover, this hydrogen gas sensor was also modified with Pt nanoparticles, which can enhance the ratio of hydrogen gas dissolve into the metal-semiconductor interface.
Finally we tried to make the porous structure with high density and high aspect ratio also by wet electroless etching technique. This porous possessed the high surface area which had the superior sensitivity.
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