1526
Enhanced Electrical and Nuclear Radiation Detection Performance in BiI3 Wide Bandgap Semiconductor Detectors

Tuesday, May 13, 2014: 14:50
Manatee, Ground Level (Hilton Orlando Bonnet Creek)
H. Han, M. Hong (Department of Materials Science & Engineering, University of Florida), S. S. Gokhale (Department of Materials Science & Engineering, Nuclear Engineering Program, University of Florida), S. B. Sinnott (Department of Materials Science & Engineering, University of Florida), J. E. Baciak (Department of Materials Science & Engineering, Nuclear Engineering Program, University of Florida), and J. C. Nino (Department of Materials Science & Engineering, University of Florida)
BiI3 is a wide band-gap compound semiconductor with a high effective atomic number that is anticipated to exhibit higher detection efficiency than other compound semiconductors such as HgI2, PbI2, and CdZnTe.  This makes BiI3 of particular interest for moderate and high energy gamma-ray detection applications.  However, the low resistivity of BiI3 results in high leakage currents and degrades the electrical properties and detecting performance of the detectors.  Here we show that the main reason for the low resistivity in BiI3 is due to the high volatility of iodine and the high concentration of intrinsic Schottky defects.  Furthermore, we will discuss novel defect engineering strategies that successfully mitigate the obstacles associated with iodine vacancies in the material.  Density functional theory (DFT) calculations, as well as experimentally measured electrical properties, and radiation response will be presented for undoped and Sb-doped BiI3 (SBI) single crystals grown via the vertical Bridgman growth technique.  Most importantly, we will demonstrate the first ever recorded gamma-ray spectrum using BiI3-based detectors.