| Summary: | 碩士 === 國立交通大學 === 材料科學與工程學系奈米科技碩博士班 === 106 === In this thesis, we fabricated a non-toxic zinc oxide (ZnO) material as the semiconducting channel layer for thin-film transistor (TFT) by using simple and low-temperature processing method. The thin-film transistors can be operated at low voltage, and it can be a photo-detector for sensing the visible light.
The thin-film transistors exhibited good electrical switching characteristics which have very low leakage current in the non-working region, in contrast, they have relatively higher saturation drain current in the working region. In this study, we used the ZnO material as the channel layer, because it is not only non-toxic and abundant but also possesses highly transparent and excellent electrical characteristics. Moreover, we can deposit the ZnO channel layer by spin-coating processing which can be carried out at the room temperature and atmosphere.
We made the photo-transistors with ZnO channel layer only sensing the UV light band and not detecting the visible band, so we linked the gold nanoparticles (AuNPs) between the channel and dielectric layer. The AuNPs can react with visible light through the surface plasmon resonance (SPR) effect. Consequently, the TFTs with AuNPs can be the photo-detector for sensing UV and visible light.
In this work, we investigated the electrical performance before and after linking AuNPs. And then investigated the ability of photo-detecting of the phototransistors with AuNPs under the various conditions of illumination. Finally, fabricated the phototransistors on fluorine tin oxide (FTO) glass substrate, and found there is still the photosensing ability.
In this work, the electrical characteristics of threshold voltage (Vth) shift represent the improvement of electrical performance and the ability of photo-sensing. The Vth could shift to -14 V when the TFT with more AuNPs. In the photo-sensing, the ZnO-based TFT with AuNPs Vth shift was 6 V after being illuminated. And the operation voltage of drain voltage was only 0.5 V. Finally, the device was fabricated on the FTO glass substrate, the Vth shift could be 0.8 V after being illuminated.
We hope to utilize low-cost, non-toxic process which can be carried out at the room temperature and atmosphere and fabricate the photodetector on FTO glass substrate. The devices on FTO glass substrate can be applied in various electronic products for industry and life.
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