Selenophosphate Pb2P2Se6 Single Crystals Growth by Chemical Vapor Transport (CVT) Method for Radiation Detection

• Published in: Chemphyschem 2024-10, Vol.25 (19), p.e202400149-n/a
• Main Authors: Ji, Leilei, Yin, Ziang, Xiao, Bao, Ge, Bangzhi, Xu, Yadong, Jie, Wanqi
• Format: Article
• Language: English
• Subjects: Alpha particles; Alpha rays; Bias; Carrier mobility; Chemical vapor transport (CVT); Crystal growth; Diffraction patterns; Electron diffraction; Electrons; Heavy metals; Hole mobility; Pb2P2Se6; Phosphides; Radiation; Radiation detection; Radiation detectors; Robustness; Single crystals
• ISSN: 1439-4235; 1439-7641; 1439-7641
• DOI: 10.1002/cphc.202400149

The heavy metal selenophosphate Pb2P2Se6 emerges as a promising room‐temperature X‐ray/γ‐ray detectors due to its high resistivity, robust radiation‐blocking capability, and outstanding carrier mobility‐lifetime product, etc. However, the high activity of phosphides poses significant impediment to the synthesis and single crystal growth. In this work, we have prepared high‐quality Pb2P2Se6 single crystals with using the chemical vapor transport (CVT) method. The XRD analysis combined with EDS result confirmed the uniform composition of the resulting as‐grown single crystals, while UV‐Vis‐NIR transmittance spectra revealed the bandgap of 1.89 eV. Selected area electron diffraction patterns indicated the crystal belonged to the P21/c(14) space group. Additionally, the Au/Pb2P2Se6/Au device is fabricated, which exhibits a robust X‐ray response with a sensitivity of 648.61 μC Gy−1 cm−2 at 400 V mm−1 under 50 kVp. Notably, the device also excels in alpha particle detection, boasting a resolution of ~14.48 % under a bias of 400 V bias. The hole mobility‐lifetime product (μτ)h of Pb2P2Se6 is estimated to be ~2.58×10−5 cm2 V−1. The results underscore potential applications of Pb2P2Se6 crystal is in the field of the semiconductor radiation detectors. The heavy metal selenophosphate Pb2P2Se6 demonstrates great potential as a room‐temperature X‐ray/γ‐ray detector due to its high resistivity, robust radiation‐blocking capability, and exceptional carrier mobility‐lifetime product. However, the high reactivity of phosphides presents significant challenges in terms of synthesis and single crystal growth. In this study, we successfully synthesized pure polycrystalline Pb2P2Se6 using a high‐temperature solid‐state reaction method for pre‐synthesis. Subsequently, large single crystals were obtained through the chemical vapor transport (CVT) method with I2 as the transport agent. XRD analysis combined with EDS results confirmed the uniform composition of the resulting as‐grown single crystals. Selected area electron diffraction patterns indicated that the crystal belonged to space group P21/c(14). The UV‐Vis‐NIR transmittance spectra revealed a bandgap of 1.89 eV and the room temperature electrical resistivity of Pb2P2Se6 crystal is 1.12×1011 Ω⋅cm, which meet the requirements for radiation detection applications. Furthermore, we fabricated an Au/Pb2P2Se6/Au device which exhibited a robust X‐ray response with a sensitivity of 648.61 μC Gy−1 cm−2 at 400 V mm−1 under 50 kVp. Im