Influence of Impurities on the Radiation Response of the TlBr Semiconductor Crystal

Abstract

Two commercially available TlBr salts were used as the raw material for crystal growths to be used as radiation detectors. Previously, TlBr salts were purified once, twice, and three times by the repeated Bridgman method. The purification efficiency was evaluated by inductively coupled plasma mass spectroscopy (ICP-MS), after each purification process. A compartmental model was proposed to fit the impurity concentration as a function of the repetition number of the Bridgman growths, as well as determine the segregation coefficients of impurities in the crystals. The crystalline structure, the stoichiometry, and the surface morphology of the crystals were evaluated, systematically, for the crystals grown with different purification numbers. To evaluate the crystal as a radiation semiconductor detector, measurements of its resistivity and gamma-ray spectroscopy were carried out, using 241Am and 133Ba sources. A significant improvement of the radiation response was observed in function of the crystal purity.

Quasi-Zero Dimensional Halide Perovskite Derivates: Synthesis, Status, and Opportunity

“…For example, purification can be made by drying the mixture under vacuum and baking at elevated temperatures to remove residual impurities (Wu et al, 2018). Another idea is to repeat crystal growth by the Bridgman technique more than once as the impurity level decreases after each repetition time (Dos Santos et al, 2017). Additionally, a pure chalcohalide compound, Tl 6 SeI 4 , was obtained with a highly efficient purification method using a bent ampoule to evaporate the main precursors, Se, Tl 2 Se and TlI and remove the main impurities such as Pb, Bi, Al, Te, Sn and Cl (Lin W. et al, 2018).…”

Development of robust perovskite single crystal radiation detectors with high spectral resolution through synergetic trap deactivation and self‐healing

“…6,7 Thallium bromide (TlBr) and mercury iodide (HgI 2 ) lack sufficient device sensitivity and carrier collection efficiency. 8,9 Cadmium zinc telluride (CZT) simultaneously possesses high carrier mobility and low dark current and can operate at room temperature; thus, since the 1990s, CZT has became a benchmark energy spectrum-resolved radiation detector with excellent energy resolution (ER). 10 However, CZT still suffers from high material and manufacturing costs, a large working bias and unbalanced electron-hole transport properties; in addition, it is difficult to directly integrate CZT with read-out circuits.…”

“…Among them, high‐purity germanium and lithium‐drift silicon function below liquid nitrogen temperature due to the narrow band gap‐induced noise, which tends to mask the signal at room temperature; as a result, the applications of these materials are dramatically limited 6,7 . Thallium bromide (TlBr) and mercury iodide (HgI 2 ) lack sufficient device sensitivity and carrier collection efficiency 8,9 . Cadmium zinc telluride (CZT) simultaneously possesses high carrier mobility and low dark current and can operate at room temperature; thus, since the 1990s, CZT has became a benchmark energy spectrum‐resolved radiation detector with excellent energy resolution (ER) 10 .…”

Purification and Improved Photoelectric Properties of Lead-Free Perovskite Cs3Bi2Br9 Crystals

“…Therefore, purification techniques, such as the low-cost mass production of halide perovskite crystals with good properties, are in high demand. Over the past few decades, different purification techniques have been developed for the fabrication of high-quality crystals (zone refining method [9,10], physical vapor transport method-PVT [11][12][13], recrystallization [14,15]), which greatly improved the optical and electrical properties of crystals. Among these techniques, the PVT method is widely used because of its cost-effectiveness and simplicity.…”