Detector based on ZnO nanorods grown by high temperature hydrothermal method

• Main Authors: Kuan-Chia Chen, 陳冠嘉
• Other Authors: 蔡振凱
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/2xfagf

碩士 === 國立虎尾科技大學 === 電子工程系碩士班 === 104 === In the study, the zinc oxide nanorods (ZnO NRs) were fabricated on glass substrate by high-temperature hydrothermal method. The enhancement of sensing performance was mainly attributed to the large effective surface area and more subtle structure of ZnO NRs surface. First, the ZnO seed film was deposited on the glass substrate by RF sputtering. Subsequently, Au film was deposited on the sample by using E-Gun evaporated through an interdigitated shadow mask onto the ZnO seed layer to form contact electrodes. Finally, the ZnO NRs was fabricated on substrate by high-temperature hydrothermal method. The ZnO NRs samples were characterized by using a high-resolution scanning electron microscopy (SEM). We found the length of ZnO NRs was approximately 946 nm. X-ray diffractometer (XRD) was used to characterize the crystallographic and structural properties of the as-grown ZnO nanorods. Photoluminescence (PL) observation of ZnO nanorods made of optical characteristics and its defect differences. The PL spectra of all the samples were shown in two emission bands, ultraviolet (UV) and visible (blue and green) bands, were observed in each spectrum. The UV emission is always ascribed to the band gap of ZnO, and the strong visible emission centered at around 550 nm is assigned to the defects (such as oxygen vacancies and interstitial zinc) in ZnO. A Keithley 2400 semiconductor parameter analyzer was then used to measure the I-V and photodetector characteristic of the fabricated device. Under an applied bias of 5 V, it was found that the measured dark current and photocurrent were 2.938×10-7 A and 3.893×10-4 A, respectively. The photocurrent to dark current contrast ratio of the fabricated photodetector exceeded 1325, and the rising time and decaying time for ZnO photodetector were 70 sec and 32 sec, respectively. The facile fabrication method and sensing properties of the obtained ZnO nanostructures is promising for the fabrication of sensor devices.