Improved Radiation Sensing with Methylammonium Lead Tribromide Perovskite Semiconductors

Recently, organometallic halide perovskites (OMHPs) have attracted much interest as a potential medium resolution detector for ionizing radiation sensing applications. Despite moderate success in the development of OMHP radiation detectors to date, efforts to optimize bulk carrier properties are often hindered by device degradation caused by surface recombination, ionic conductivity, environmental instability, and interface phenomena. In this study, methods of improving the interfacial and surface properties, detector stability, and responsivity of methylammonium lead tribromide (MAPB) semiconductor radiation detectors were investigated. We demonstrated that chemomechanical polishing with dimethylformamide (DMF) as a finishing step decreased surface roughness, removed surface trap states, and greatly enhanced device stability compared to mechanical polishing. Further, using a tin oxide (SnO2) interface layer as hole blocking/electron transporting layer greatly increased the device fabrication success rate and helped mitigate the effect of ion migration reactions with metallic contacts. These post-growth processing techniques resulted in the first electron response of a MAPB detector exposed to alpha particles.