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

Abstract

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.