Multiple-band and spectrally distinctive photodetection play critical roles in building next-generation colorful imaging, spectroscopy, artificial vision, and optically controlled logic circuits of the future. Unfortunately, it remains challenging for conventional semiconductor photodetectors to distinguish different spectrum bands with photon energy above the bandgap of the material. Herein, for the first time, a photocurrent polarity-switchable photoelectrochemical device composed of group III-nitride semiconductors, demonstrating a positive photocurrent density of 10.54 µA cm−2 upon 254 nm illumination and a negative photocurrent density of −0.08 µA cm−2 under 365 nm illumination without external power supply, is constructed. Such bidirectional photocurrent behavior arises from the photovoltage-competing dynamics across two photoelectrodes. Importantly, a significant boost of the photocurrent and corresponding responsivity under 365 nm illumination can be achieved after decorating the counter electrode of n-type AlGaN nanowires with platinum (Pt) nanoparticles, which promote a more efficient redox reaction in the device. It is envisioned that the photocurrent polarity-switch behavior offers new routes to build multiple-band photodetection devices for complex light-induced sensing systems, covering a wide spectrum band from deep ultraviolet to infrared, by simply engineering the bandgaps of semiconductors.
Bibliographical noteKAUST Repository Item: Exported on 2021-10-26
Acknowledgements: This work was funded by the National Natural Science Foundation of China (Grant Nos. 51961145110 and 61905236), the Fundamental Research Funds for the Central Universities (Grant No. WK2100230020), and the USTC Research Funds of the Double First-Class Initiative (Grant No. YD3480002002), and was partially carried out at the USTC Center for Micro and Nanoscale Research and Fabrication.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics