Self-assembled AlGaN nanowires (NWs) are regarded as promising structures in the pursuit of ultraviolet photodetectors (UV PDs). However, AlGaN nanowire-based PDs currently suffer from degraded performance partially owing to the existence of outstanding surface-related defects/traps as a result of its large surface-to-volume-ratio feature. Here, we propose an effective passivation approach to suppress such surface states via tetramethyl ammonium hydroxide (TMAH) solution treatment. We successfully demonstrate a fabrication of UV PDs using TMAH-passivated AlGaN quantum-disk NWs and investigate their optical and electrical properties. Particularly, the dark current can be significantly reduced by an order of magnitude after surface passivation, thus leading to the improvement of photoresponsivity and detectivity. The underlying mechanism for such boost can be ascribed to the effective elimination of oxygen-related surface states on the nanowire surface. Consequently, an AlGaN nanowire UV PD with a low dark current of 6.22×10-9 A, a large responsivity of 0.95 A W-1, and a high detectivity of 6.4×1011 Jones has been achieved.
Bibliographical noteKAUST Repository Item: Exported on 2021-12-15
Acknowledgements: This work was funded by National Natural Science Foundation of china (Grant No. 61905236, 51961145110), Fundamental Research Funds for the Central Universities (Grant No. WK2100230020), 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
- Surfaces, Coatings and Films
- Acoustics and Ultrasonics
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics