Direct thermal neutron detection by the 2D semiconductor 6LiInP2Se6

• Published in: Nature (London) Vol. 577; no. 7790; pp. 346 - 349
• Main Authors: Chica, Daniel G., He, Yihui, McCall, Kyle M., Chung, Duck Young, Pak, Rahmi O., Trimarchi, Giancarlo, Liu, Zhifu, De Lurgio, Patrick M., Wessels, Bruce W., Kanatzidis, Mercouri G.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 16.01.2020; Nature Publishing Group
• Subjects: 639/301/1005/1007; 639/638/263; Absorption cross sections; Astronomy; Charge transport; Crystallography; Detectors; Energy resolution; Humanities and Social Sciences; Iodine; MATERIALS SCIENCE; Materials selection; multidisciplinary; Neutron counters; Neutrons; Nuclear capture; Nuclides; Room temperature; Science; Science (multidisciplinary); Scintillation counters; Semiconductors; Sensors; Single crystals; Thermal neutrons
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/s41586-019-1886-8

Highly efficient neutron detectors are critical in many sectors, including national security 1 , 2 , medicine 3 , crystallography 4 and astronomy 5 . The main neutron detection technologies currently used involve 3 He-gas-filled proportional counters 6 and light scintillators 7 for thermalized neutrons. Semiconductors could provide the next generation of neutron detectors because their advantages could make them competitive with or superior to existing detectors. In particular, solids with a high concentration of high-neutron-capture nuclides (such as 6 Li, 10 B) could be used to develop smaller detectors with high intrinsic efficiencies. However, no promising materials have been reported so far for the construction of direct-conversion semiconductor detectors. Here we report on the semiconductor LiInP 2 Se 6 and demonstrate its potential as a candidate material for the direct detection of thermal neutrons at room temperature. This compound has a good thermal-neutron-capture cross-section, a suitable bandgap (2.06 electronvolts) and a favourable electronic band structure for efficient electron charge transport. We used α particles from an 241 Am source as a proxy for the neutron-capture reaction and determined that the compact two-dimensional (2D) LiInP 2 Se 6 detectors resolved the full-energy peak with an energy resolution of 13.9 per cent. Direct neutron detection from a moderated Pu–Be source was achieved using 6 Li-enriched (95 per cent) LiInP 2 Se 6 detectors with full-peak resolution. We anticipate that these results will spark interest in this field and enable the replacement of 3 He counters by semiconductor-based neutron detectors. The semiconductor 6 LiInP 2 Se 6 is used for the direct detection of thermal neutrons at room temperature, demonstrating good energy resolution.