Enhanced gamma ray sensitivity in bismuth triiodide sensors through volumetric defect control

Abstract

Some of the more attractive semiconducting compounds for ambient temperature radiation detector applications are impacted by low charge collection efficiency due to the presence of point and volumetric defects. This has been particularly true in the case of BiI3, which features very attractive properties (density, atomic number, band gap, etc.) to serve as a gamma ray detector, but has yet to demonstrate its full potential. We show that by applying growth techniques tailored to reduce defects, the spectral performance of this promising semiconductor can be realized. Gamma ray spectra from >100 keV source emissions are now obtained from high quality Sb:BiI3 bulk crystals with limited concentrations of defects (point and extended). The spectra acquired in these high quality crystals feature photopeaks with resolution of 2.2% at 662 keV. Infrared microscopy is used to compare the local microstructure between radiation sensitive and non-responsive crystals. This work demonstrates that BiI3 can be prepared in melt-grown detector-grade samples with superior quality and can acquire the spectra from a variety of gamma ray sources.

Van der Waals Epitaxy of Horizontally Orientated Bismuth Iodide/Silicon Heterostructure for Nonvolatile Resistive‐Switching Memory with Multistate Data Storage

“…[ 40–44 ] Thus far, BiI 3 has been applied to gamma‐ray detection, pressure sensors, photodetectors, and photovoltaics. [ 38–40,43–54 ] Its Bi–I–Bi intralayer is ionically bonded, and the interlayer is hold by weak van der Waals force along its (00l) direction, resulting in electrically anisotropic property of BiI 3 crystals, especially low electrical conductivity in (001) direction. High resistance and ionic composition of BiI 3 suggest that the BiI 3 has great potential as an insulator in RRAM.…”

The electronic structure and band interface of cesium bismuth iodide on a titania heterostructure using hard X-ray spectroscopy

“…The ternary bismuth halide Cs 3 Bi 2 I 9 has been investigated by several groups because of its application in solar cells and optoelectronics with encouraging results. [17][18][19] The related BiI 3 has also been effective in its use for various optoelectronic applications itself, [20][21][22] while CsI has been used for high-energy detectors for decades. 23 In alternative metal cation substitutions, the oxidation sensitive tin iodides 24 or the moisture sensitive Sb 3+ iodides are serious concerns, nevertheless they have merits of their own in their crystal and electronic properties.…”

Dopant compensation in alloyed CH3NH3PbBr3−xClx perovskite single crystals for gamma-ray spectroscopy

“…Therefore, the objective of obtaining a good-resolution energy spectrum imposes strict requirements to radiation detection materials, as well as the sizes of materials in terms of competition with Schubweg distance. Semiconductor radiation detectors for high-energy-photon detection require materials with a large detecting volume to intercept radiation, a large linear attenuation coefficient, large and balanced electron and hole mobility (µ)-charge carrier lifetime (τ ) product (µτ product) for efficient charge collection, and finally, high resistivity and low charge trap density to avoid charge trapping under singleevent analysis 4 . Among the semiconductors with relatively strong attenuation, high-purity germanium (HPGe) that was developed in the 1970s gives a γ-ray detector the best resolution, which however needs liquid nitrogen cooling due to its small bandgap 5 .…”