Mechanism of high sensitivity of ZnO Schottky nanodevices under UV light
Chieh-Wei Chen1,2*, Shuen-Jium You1,2, Ying-Jhe Wang1,2, Ming-Pei Lu3, Ming-Yen Lu1,2
1Graduate Institute of Opto-Mechatronics, National Chung Cheng University, Chia-Yi, Taiwan
2Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, Chia-Yi, Taiwan
3National Nano Device Laboratories, National Applied Research Laboratories, Hsinchu, Taiwan
* presenting author:陳玠瑋,
In this study we measured the degrees to which the Schottky barrier heights (SBHs) are lowered in ZnO nanowire (NW) devices under illumination with UV light. We measured the I–V characteristics of ZnO nanowire devices to confirm that ZnO is an n-type semiconductor and that the on/off ratio is approximately 104. We obtained a Schottky barrier height for a ZnO NW Schottky device in the dark (0.661 eV) from temperature-dependent I–V measurements. Variations in the SBH account for the superior characteristics of n-type Schottky devices under illumination with UV light. Furthermore, through temperature-dependent I–V measurements, we determined the SBHs in the dark and under illumination with UV light at power densities of 0.5, 1, 2, and 3 μW/cm² to be 0.661, 0.216, 0.178, 0.125, and 0.068 eV, respectively. These findings should be applicable in the design of highly sensitive nanoscale optoelectronic devices.

Keywords: ZnO, nanowire, Schottky barrier lowering, photodetector