Growth and Characterization of Inorganic Perovskite Crystals for Radiation Detection Applications

Inorganic semiconductor materials such as CsPbBr₃ (CPB) and Cs₃Bi₂I₉ (CBI) are promising for detection of gamma rays and charge particles at ambient temperature due to a wide bandgap, high mobility-lifetime product, and low density of defects in crystals enabling their long-term stability and large crystal designs. The growth of CBP and CBI crystals from their own melt by Bridgman method using a three-zone vertical furnace with a computer control of temperature gradient between hot zone and cold zone, cooling rate, and a vertical translation of a vacuum-sealed quartz ampoule was studied taking into account phase transformations during the process. The synthesized ingots were processed into wafers using a diamond saw. The wafer surface treatment and polishing procedures, and electrode deposition techniques will be discussed. The perovskite crystals were characterized using the room-temperature and cryogenic photoluminescence, optical and scanning electron microscopy. We will discuss compositional uniformity of crystals characterized using XRD, EDS, and SIMS techniques. Electrical characterization of the CPB and CBI wafers was performed for I-V analysis.