Synthesize and Characterization of ZnO Nanotubes/Cu-based Metallic Glass Thin Film hybrid Photodetectors

• Main Authors: You-Syuan - Chen, 諶又瑄
• Other Authors: Bohr-Ran Huang
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/19777159740572230928

碩士 === 國立臺灣科技大學 === 光電工程研究所 === 105 === UV photodetectors are desirable to detect the UV radiation level that can affect the human body, also it is utilized in multiple areas such as industrial, army, ecological and biological applications. ZnO materials based UV devices have fascinated extensive attention due to their easy synthesized method, and attractive optical and electrical properties. However, recently the performance of ZnO based photodetectors (PDs) behaviors significantly depends on their hybrid combinations that overcome the poor performance of bare ZnO based devices. In order to improve the ZnO based UV device properties, herein we fabricated UV PDs using ZnO and metallic glass thin films (TFMG). Initially, we have systematically analyzed the basic properties of Cu-based TFMG (Cu-TFMG) and ZnO materials based UV PDs. It was found that ZnO nanotubes (ZnTs) have larger specific surface area and depletion width than ZnO nanorods (ZnRs), therefore the IPhoto/IDark ratio of the UV PDs is increased from 252.8 to 2.03×103. Later, the Cu-TFMG were coated on ZnO nanostructures with different thickness, 3nm, 6nm, 10nm and 15nm respectively. The Cu-TFMG on ZnO nanotubes (ZnTs) based UV photodetectors exhibit better the IPhoto/IDark ratio (7.11×103) than Cu-TFMG on ZNRs (6.72×103). Furthermore, the effects of different thicknesses of Cu-TFMG under the ZnO nanostructures are investigated thoroughly. The IPhoto/IDark ratio of ZnRs/Cu-TFMG is 9.16×103, and it is interesting that the IPhoto/IDark ratio of ZnTs/Cu-TFMG is increased excellently upto 1.99×104. On the other hand, the properties of ZnO/Cu-TFMG are improved by simple annealing and IPhoto/IDark ratios are increase overwhelmingly. The IPhoto/IDark ratio of ZnRs/TFMG (150°C) is 2.45×104 and the IPhoto/IDark ratio of ZnTs/Cu-TFMG (150°C) is 2×105, which is nearly 800 times better than as grown ZnRs. It is believed that the sputtering Cu-TFMG with ZnO nanostructures can form a Schottky barrier junction at the interface, thereby reducing dark current. When the light is incident on the ZnTs/Cu-TFMG, it is possible to increase the light path and increase the photoresponse excellently. However, when UV apply on Cu-TFMG/ZnTs, light was absorbed by TFMG. So that light is confined at the interface, resulting in photo current decrease. The ZnTs/Cu-TFMG combination is believed to be an outstanding combination for harvesting photons and creating electron–hole pairs. The proposed ZnTs/Cu-TFMG photodetectors exhibits excellent photoresponse and fast switching speed in the UV region, and is a new promising hybrid material for high-performance optoelectronic devices.