Concurrent Improvement in Photogain and Speed of a
Metal Oxide Nanowire Photodetector through Enhancing Surface Band
Bending via Incorporating a Nanoscale Heterojunction
- Publication date
- Publisher
Abstract
The
surface effect on the photodetection of metal oxide nanostructures
acting as a double-edged sword achieves ultrahigh photogain but unavoidably
prolongs the response time due to slow oxygen adsorption/desorption
processes. In this study, we break the compromise to enhance the UV
photogain by 3 orders of magnitude as well as increase the photoresponse
speed by 5 times via incorporating open-circuit p–n nanoscale
heterojunctions (NHJs) by forming single-crystalline p-NiO nanoparticles
on n-ZnO nanowires. This is because the formation of NHJs enhances
surface band bending of ZnO nanowires, improving the spatial separation
efficiency of photogenerated electrons and holes, and passivates the
ZnO surfaces by minimizing the interaction of photocarriers with chemisorbed
oxygen molecules. The concept using NHJs explores a new pathway toward
ultrafast and supersensitive photodetection