Realization of highly efficient hexagonal boron nitride neutron detectors
نویسندگان
چکیده
We report the achievement of highly efficient B enriched hexagonal boron nitride (h-BN) direct conversion neutron detectors. These detectors were realized from freestanding 4-in. diameter h-BN wafers 43 lm in thickness obtained from epitaxy growth and subsequent mechanical separation from sapphire substrates. Both sides of the film were subjected to ohmic contact deposition to form a simple vertical “photoconductor-type” detector. Transport measurements revealed excellent vertical transport properties including high electrical resistivity (>10 X cm) and mobilitylifetime (ls) products. A much larger ls product for holes compared to that of electrons along the c-axis of h-BN was observed, implying that holes (electrons) behave like majority (minority) carriers in undoped h-BN. Exposure to thermal neutrons from a californium-252 (Cf) source moderated by a high density polyethylene moderator reveals that 43 lm h-BN detectors possess 51.4% detection efficiency at a bias voltage of 400V, which is the highest reported efficiency for any semiconductor-based neutron detector. The results point to the possibility of obtaining highly efficient, compact solid-state neutron detectors with high gamma rejection and low manufacturing and maintenance costs. Published by AIP Publishing. [http://dx.doi.org/10.1063/1.4960522]
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