BiI_3 single crystal for room-temperature gamma ray detectors

摘要

BiI_3 single crystals were grown by the physical vapor transport method. The repeated sublimation of the starting material reduced impurities in the Bi_3 single crystal to sub-ppm levels. The detector was fabricated by depositing Au electrodes on both surfaces of the 100-μm-thick BiI_3 single crystal platelet. The resistivity of the BiI_3 single crystal was increased by post-annealing in an iodine atmosphere (ρ=1.6× 10~(11) Ωcm). Pulse height spectroscopy measurements showed clear peaks in the energy spectrum of alpha particles or gamma rays. It was estimated that the mobility-lifetime product was μ_eτ_e=3.4-8.5 × 10~(-6) cm~2/V and the electron-hole pair creation energy was 5.8 eV. Our results show that BiI_3 single crystals are promising candidates for detectors used in radiographic imaging or gamma ray spectroscopy.