Fabrication and characterization of novel devices with selectively grown ZnO-Based nanobridges
| Autor: | Wei- Bin Cheng, 鄭偉繽 |
|---|---|
| Rok vydání: | 2009 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 97 We report the fabrication and characteristics of field-effect Transistor (FET) and metal-semiconductor-metal photodetectors (MSM PDs) with selectively grown ZnO-Based nanobridges. The ZnO seed layer was deposited by radio frequency magnetron sputtering. We used low-temperature solution method to fabricated well-aligned crystalline ZnO nanobridges (ZnO NBs) arrays. The lengths of ZnO NBs could be controlled by low-temperature solution method. Furthermore, the crystalline ZnO NBs also promoted the carrier transmission. We used、high-resolution X-ray diffraction (XRD) and Micro-Raman to characterize the crystalline ZnO NBs. Devices used the microlithography technology to protect metal from chemical solution, which can achieve the ZnO NBs field-effect transistor and metal-semiconductor-metal photodetectors. First part, in the photodetectors component, we measured photo and dark current ratio, optical responsivities. It was found that the ZnO NBs photodetectors had larger responsivity 166A/W and bule-shift in the responsivity. We also found that the ZnO NBs photodetectors had high UV-to-visible rejection ratio was 1353.6 .such a high photoresponse could strongly depend on oxygen adsorption/desorption process in the presence of trap states at the NBs surface. In the bule-shift on the responsivity component, we can found that the ZnO NBs photodetectors had stress in the ZnO NBs by using Micro-Raman. Finally, from the analyises of photoelectric characteristic of this novel ZnO NBs photodetectors, we concluded that the novel ZnO NBs photodetectors have better than the ZnO thin film photodetectors. However, these novel devices still need to be studied in the future. Second part fabricated the FET device; we report the fabrication and characteristics of ZnO thin-film transistors (TFTs) and ZnO nanobridges field-effect transistorand (ZnO NBs FET) with different SiO2 thicknesses and anneal process. The ZnO films were deposited as active channel layers on Indium Tin Oxide (ITO) substrates by rf magnetron sputtering at room temperature. We using a bottom-gate configuration were investigated. The ZnO TFT and ZnO NBs FET exhibited enhancement mode characteristics. It was found that the ZnO TFT threshold voltage (Vth), transconductance (gm), saturation current (IDS), on/off ratio, subthreshold swing, and field effect mobility. This research implies that ZnO-Based transistorands produced by a simple and low-cost technique which can be applicable to electronic devices. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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