Enhancing the self-powered performance in VOx/Ga2O3 heterojunction ultraviolet photodetector by hole-transport engineering

• Published in: Journal of alloys and compounds 2022-05, Vol.902, p.163801, Article 163801
• Main Authors: Li, Shan, Yue, Jianying, Yan, Zuyong, Liu, Zeng, Lu, Chao, Li, Peigang, Guo, Daoyou, Wu, Zhenping, Guo, Yufeng, Tang, Weihua
• Format: Article
• Language: English
• Subjects: Current carriers; Dark current; Ga2O3; Gallium oxides; Heterojunction; Heterojunctions; Hole transport layer; Photodetector; Photoelectricity; Photometers; Self-powered; Ultraviolet detectors; Valence band; VOx
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2022.163801

•Solution processed VOx films obtain changeable conductivities in 2 orders of magnitude range.•Regulable conductivity of VOx enables effective hole-transport engineering in VOx/Ga2O3 heterojunction.•Optimized VOx/Ga2O3 photodetector demonstrates enhanced self-powered ultraviolet photodetection performance. The self-powered photodetection performance of the VOx/Ga2O3 heterojunction photodetector could be effectively and positively regulated via the VOx hole transport layer by charge-carrier engineering, inducing the record PDCR of 1.08 × 108 and superhigh on/off ratio of 1.23 × 106. [Display omitted] As the carrier behavior is crucial to the photoelectric conversion process, the charge-carrier engineering could provide feasible strategy for high-performance photodetector (PD). Herein, self-powered ultraviolet PDs were constructed on VOx/Ga2O3 (VGO) heterojunctions by adopting the solution processed VOx films as hole transport layer (HTL). Treated with different annealing ambients, the HTL demonstrated changeable conductivities due to the regulated crystallinities, phase structures and chemical valences, which further exerted influences on the VGO PDs inducing controllable photodetection properties. With effective hole transportation, low valence band barrier and large built-in field, the modulated VGO PDs achieved enhanced self-powered photodetection performance with photo-to-dark current ratio of 1.08 × 108, on/off ratio of 1.23 × 106, rejection ration (R245/R400) of 3.12 × 104, responsivity of 28.9 mA/W and detectivity of 1.13 × 1014 Jones as well as rise/decay time of 57/74 ms. In consideration of the carrier-transport problems are commonly ubiquitous and particularly vital, our proposed HTL engineering method could open the high-performance route for self-powered ultraviolet PDs.