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

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 (O-2-SrSnO3) decreased from 54.2% to 22.8%, while the conductivity of the Y doped SrSnO3 (Y-O-2-SrSnO3) increased about one order of magnitude. Thanks to this ETL engineering, the Y-O-2-SrSnO3 exhibits the best carrier transportation efficiency, and the photodetector based on beta-Ga2O3/Y-O-2-SrSnO3 shows excellent photoelectrical performances with an I-on/I-off ratio of 4.3 x 10(6), a detectivity of 1.3 x 10(13) Jones, and a solar-blind/visible (R238 nm/R400 nm) rejection ratio of 4.1 x 10(3). Our work provides a general strategy for building construct highly sensitive photodetectors, thus may push forward their applications.

Automated summary

The selection of an appropriate electron transport layer (ETL) is crucial for the performance of photodetectors. However, developing efficient materials for deep UV photodetectors remains challenging. In this study, wide-bandgap SrSnO3 nanoparticles were used to construct heterojunction solar-blind photodetectors with Ga2O3. The SrSnO3 was annealed and doped with Y elements to improve carrier transportation efficiency. The resulting Y-O-2-SrSnO3 showed excellent photoelectrical performances in the photodetector based on beta-Ga2O3/Y-O-2-SrSnO3.