High sensitivity neutron detectors based on hexagonal boron nitride epilayers

Hexagonal boron nitride (h-BN) has emerged as a promising material for realizing high efficiency solid-state thermal neutron detectors. Here, we report the epitaxial growth of thick h-¹⁰BN (¹⁰B enriched) epilayers and demonstration of thermal neutron detectors with a record high detection efficiency. To increase the overall detection sensitivity, we have explored strategies in material growth and device processing to reduce the detector’s dark current, capacitance, and surface recombination field and realized h-¹⁰BN detectors from 100 µm thick freestanding wafers with a detection area as large as 1 cm² and a detection efficiency as high as 59%. We discuss the detail design and implementation of horizontal h-¹⁰BN detectors to overcome the detrimental effects associated with increased dark current, capacitance, and surface recombination with increasing detector size, through reduction in metal contact area of the detector and utilization of superior lateral transport properties of h-BN. This work lays the foundation for achieving highly sensitive large h-¹⁰BN neutron detectors for practical applications.