| Summary: | 碩士 === 國立雲林科技大學 === 電子與光電工程研究所碩士班 === 101 === In this study, vertically aligned Ga-doped ZnO nanorods are grown on glass substrate by a low temperature process, hydrothermal method. The synthesis solution of Ga-doped ZnO nanorods were fabricated by zinc nitrate hexahydrate (Zn(NO3)2・6H2O), gallium nitrate hydrate (Ga(NO3)3・xH2O) and methenamine (C6H12N4, HMTA). The growth temperatures and times are 70℃, 80℃, 90℃ and 8 hours, respectively.
The morphology of Ga-doped ZnO nanorods can be showed by the FESEM images. It shows the Ga-doped ZnO nanorods grown at 90℃ are needle-like shape. The Ga-doped ZnO nanorods can be show hexagonal wurtzite structures by elected-area electron diffraction (SAED) pattern of TEM and XRD. The analysis of XRD, Raman and PL conclude that the Ga-doped ZnO nanorods grown at 90℃ has high crystalline quality.
By the previous analysis, it can know that Ga-doped ZnO nanorods grown at 90℃ have high crystalline quality and needle-like shape. Therefore, the growth condition is chosen to fabricate the applied device. In this study, the photodetector, humidity sensor and field emission are measured, and then they are analyzed. The field emission performance can be enhanced by Ga dopant and needle-like shape. It was found that the turn-on electrical field was reduced from 3.63 to 3.15 V/μm and the field enhancement factor was enhanced from 9058 to 13529 by UV illumination. Under UV illumination, the Ga-ZnO nanorods photodetectors exhibit a high UV photocurrent, fast rise time, and high UV-to-visible ratio.
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