Solution-processed Y-doped SnSrO3 electron transport layer for Ga2O3 based heterojunction solar-blind photodetector with high sensitivity

• Published in: Vacuum Vol. 201; p. 111064
• Main Authors: Wu, Chao, Wu, Fengmin, Deng, Lipeng, Li, Shan, Wang, Shunli, Cheng, Lin, Liu, Aiping, Wang, Jinbin, Tang, Weihua, Guo, Daoyou
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2022
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2022.111064

Since the transport behavior of carriers is crucial to the photodetection process, selecting a suitable electron transport layer (ETL) is an effective strategy for preparing high-performance photodetectors. However, developing high-efficiency and comprehensive bandgap ETL materials for deep UV photodetectors remains challenging. In this work, we used wide-bandgap SrSnO3 nanoparticles to construct heterojunction solar-blind photodetectors with Ga2O3 by a simple solution-processing method. To improve carrier transportation efficiency, the SrSnO3 was annealed in an oxygen atmosphere and doped with Y elements to reduce oxygen vacancies and increase conductivity. Compared to the untreated SrSnO3, the oxygen vacancy of SrSnO3 annealed under oxygen (O2–SrSnO3) decreased from 54.2% to 22.8%, while the conductivity of the Y doped SrSnO3 (Y–O2–SrSnO3) increased about one order of magnitude. Thanks to this ETL engineering, the Y–O2–SrSnO3 exhibits the best carrier transportation efficiency, and the photodetector based on β-Ga2O3/Y–O2–SrSnO3 shows excellent photoelectrical performances with an Ion/Ioff ratio of 4.3 × 106, a detectivity of 1.3 × 1013 Jones, and a solar-blind/visible (R238 nm/R400 nm) rejection ratio of 4.1 × 103. Our work provides a general strategy for building construct highly sensitive photodetectors, thus may push forward their applications. •To the best of my knowledge, this is the first work that uses the SrSnO3 in the solar-blind photodetector field.•To improve the carrier transportation efficiency of SrSnO3, we annealed the SrSnO3 in an oxygen atmosphere and doped it with Y elements.•To investigate the mechanism of the effect of oxygen vacancy on the bandgap, a theoretical calculation on SrSnO3 was carried out.•The photodetector based on β-Ga2O3/Y–O2–SrSnO3 heterojunction shows excellent photoelectrical performances with an Ion/Ioff ratio of 4.3 × 106.