Performance optimization of self-powered ultraviolet and short-wavelength blue photodetectors based on ZnO/SrTiO 3 heterojunctions by annealing treatment

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 12; no. 19; pp. 6911 - 6919
• Main Authors: Cong, Lujia, Han, Yurui, Zhao, Huimin, Gao, Chunyue, Zhang, Wei, Zhang, Shan, Wang, Hongbin
• Format: Journal Article
• Language: English
• Published: 16.05.2024
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/D4TC00959B

In this study, self-powered photodetectors (PDs) sensitive to ultraviolet (UV) and short-wavelength blue (SWB) light were developed using a ZnO/SrTiO 3 heterojunction, created through the magnetron sputtering technique. The photoresponse of the ZnO/SrTiO 3 PDs showed significant enhancement following an annealing process. Post-annealing, the response ( R ) value of the ZnO/SrTiO 3 PDs was recorded at 0.7 mA W −1 , indicating an increase of 3.5 times compared to the pre-annealed state. Additionally, the rejection ratio between 390 nm and 450 nm ( R 390 nm/ R 450 nm) improved markedly from 6.21 to 38.16, demonstrating enhanced UV-SWB spectral discrimination. The rise and decay times for the annealed devices were measured at 35 μs and 3.5 ms, respectively. The observed enhancements in the performance of ZnO/SrTiO 3 PDs are primarily attributed to the improved crystal quality of ZnO and the optimized intrinsic defect structures within the ZnO films due to annealing. This led to a strengthened internal electric field, facilitating the efficient separation and movement of photogenerated charge carriers. The outcomes of this study offer significant insights for the design and production of self-powered UV-SWB photodetectors.