Controlling the Vapor Transport Crystal Growth of Hg₃Se₂I₂ Hard Radiation Detector Using Organic Polymer

Abstract

The chalcohalide compound Hg3Se2I2 with a defect anti-perovskite structure has been demonstrated to be a promising semiconductor for room temperature X- and γ-ray detection. In this work, we use transport agents during the vapor growth of Hg3Se2I2 crystals under gradient temperature profiles to dramatically improve the size and yield of Hg3Se2I2 single crystals. Various growth conditions with combinations of organic polymer (polyethylene) with elemental Hg, Se, or I2 are compared. The largest single crystals (with size up to 7 × 5 × 3.5 mm3) were obtained using both polyethylene and excess I2 as the transport agents. The as-prepared detector devices based on these crystals have excellent photo response to a series of radiation sources, including low flux X-ray source, alpha particles, and γ-rays. The X-ray induced photocurrent of Hg3Se2I2 detectors is 3 orders of magnitude higher than the dark current, indicating excellent X-ray photosensitivity. Under 241Am α particle source (5.5 MeV), the best energy resolution obtained is ∼8.1%. The Hg3Se2I2 device also shows improved detector performance under 57Co and 137Cs γ-ray sources. The improved crystal growth and detector performance using this polymer additive during the vapor transport process further confirms the great potential for the development of Hg3Se2I2 for radiation detection.

Recent Development of Halide Perovskite Materials and Devices for Ionizing Radiation Detection

“…135 Furthermore, it is found that adding an organic polymer such as polyethylene (PE) can lead to significantly larger size and improved detector performance with the size up to 7 × 5 × 3.5 mm. 151 The Bridgman method, a melt-based technique, is also widely reported for the growth of inorganic perovskite SCs. 98 In this process, the sealed silica tube filled with the perovskite precursor is moved along the temperature gradient.…”

“…184 In addition, antiperovskite SCs such as TlSn 2 I 5 and Hg 3 Se 2 I 2 have also been made into vertical detectors, which display excellent performance for X-ray, γ-ray, and α-particle detection. 151,152 Studies to compare the performance of lateral and vertical photoconductors for X-ray detection were also conducted. 100 Recently, a very sensitive anisotropic X-ray detector made of 2D (NH 4 ) 3 Bi 2 I 9 SC has been reported.…”

“…Furthermore, they developed an improved vapor transport method assisted by the organic polymer of polyethylene (PE) to obtain large Hg 3 Se 2 I 2 SCs with a size up to ∼1 cm. 151 They also prepared 2D TlSn 2 I 5 SCs with high Z values (Tl: 81, Sn: 50, I: 53), large crystal size, and of high quality by the vertical Bridgman method. 152 TlSn 2 I 5 SCs are free of phase transitions between melting and ambient temperature, which also suppresses the formation of thermally activated defects due to their low melting point.…”

“…By exploring the ideal temperature and transport time, large-size and crack-free Hg 3 Q 2 I 2 (Q = S, Se, and Te) SCs have been successfully obtained for radiation detection . Furthermore, it is found that adding an organic polymer such as polyethylene (PE) can lead to significantly larger size and improved detector performance with the size up to 7 × 5 × 3.5 mm …”

Vapor‐Phase Growth Strategies of Fabricating Organic Crystals for Optoelectronic Applications

“…[ 18–24 ] Benefiting from the advantages from the vapor‐phase growth method, the organic crystals made from the sublimated vapor can become the crucial parts in manufacturing high‐performance photonic and optoelectronic devices, such as organic solid‐state lasers (OSSLs), [ 25–27 ] organic optical waveguides, [ 28 ] organic field‐effect transistors (OFETs), [ 29,30 ] and organic photoelectric detectors. [ 31–33 ]…”