Bismuth tri-iodide crystal for nuclear radiation detectors

Bismuth tri-iodide (BiI₃) is an attractive material for room temperature radiation detectors because of its wide bandgap energy and high photon stopping power. In this paper, BiI₃ crystals have been grown by the vertical Bridgman technique using commercially available powder. The grown crystals have been characterized in terms of their structural properties and stoichiometry. Room temperature radiation detectors have been fabricated from the crystals and tested by measuring their leakage currents and spectral responses. A clear peak corresponding to 5.48 MeV α-particles (²⁴¹Am) was recorded with an 82 μm thick BiI₃ detector with Pd electrodes of 1 mm in diameter. The energy resolution of the 5.48 MeV peak was found to be 2.2 MeV FWHM.