Robust Thermal Neutron Detection by LiInP2 Se6 Bulk Single Crystals.

Abstract

Direct neutron detection based on semiconductor crystals holds promise to transform current neutron detector technologies and further boosts their widespread applications. It is, however, long impeded by the dearth of suitable materials in the form of sizeable bulk crystals. Here, we have developed high-quality centimeter-sized LiInP2 Se6 single crystals using the Bridgman method and systematically investigated their structure and property characteristics. The prototype detectors fabricated from the crystals demonstrate an energy resolution of 53.7% in response to α-particles generated from an 241 Am source and robust, well-defined response spectra to thermal neutrons that exhibit no polarization or degradation effects under prolonged neutron/γ-ray irradiation. We have also identified the primary mechanisms of Se-vacancy and InLi antisite defects in the carrier trapping process. Such insights are critical for further enhancing the energy resolution of LiInP2 Se6 bulk crystals towards the intrinsic level (∼8.6% as indicated by our chemical vapor transport-grown thin crystals). These results pave the way for practically adopting LiInP2 Se6 single crystals in new-generation solid-state neutron detectors. This article is protected by copyright. All rights reserved.