Robust Thermal Neutron Detection by LiInP₂ Se₆ Bulk Single Crystals

Area of Science:

• Materials Science
• Nuclear Instrumentation
• Solid-State Physics

Background:

• Direct neutron detection using semiconductor crystals is crucial for advancing detector technologies.
• The development of suitable materials in bulk crystal form has been a significant limitation.
• Semiconductor-based neutron detectors offer potential advantages over traditional methods.

Purpose of the Study:

• To develop and characterize high-quality, centimeter-sized LiInP2Se6 single crystals.
• To evaluate the performance of prototype neutron detectors fabricated from these crystals.
• To identify defect mechanisms influencing detector performance and guide future improvements.

Main Methods:

• Bridgman crystal growth method for producing LiInP2Se6 single crystals.
• Systematic investigation of crystal structure and property characteristics.
• Fabrication and testing of prototype detectors using alpha-particle and thermal neutron sources.

Main Results:

• Successful growth of centimeter-sized LiInP2Se6 single crystals.
• Prototype detectors achieved 53.7% energy resolution for alpha particles.
• Demonstrated robust and stable response to thermal neutrons without polarization or degradation.
• Identified Se-vacancy and InLi antisite defects as primary mechanisms for carrier trapping.

Conclusions:

• LiInP2Se6 single crystals are a promising material for next-generation solid-state neutron detectors.
• Understanding defect mechanisms is key to enhancing energy resolution towards intrinsic levels.
• These findings pave the way for practical adoption of LiInP2Se6 in neutron detection applications.