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This content will become publicly available on August 16, 2017

Title: Realization of highly efficient hexagonal boron nitride neutron detectors

Here, we report the achievement of highly efficient 10B enriched hexagonal boron nitride (h- 10BN) direct conversion neutron detectors. These detectors were realized from freestanding 4-in. diameter h- 10BN wafers 43 μm 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 (>1013 Ω cm) and mobility-lifetime (μτ) products. A much larger μτ 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 (252Cf) source moderated by a high density polyethylene moderator reveals that 43 μm h- 10BN detectors possess 51.4% detection efficiency at a bias voltage of 400 V, 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.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Texas Tech Univ., Lubbock, TX (United States)
Publication Date:
OSTI Identifier:
1330680
Grant/Contract Number:
NA0002927; 2011-DN- 077-ARI048; ECCS-1402886
Type:
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 109; Journal Issue: 7; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Research Org:
Texas Tech Univ., Lubbock, TX (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE); USDOE National Nuclear Security Administration (NNSA); National Science Foundation (NSF); Department of Homeland Security (DHS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE wide bandgap semiconductors; solid-state neutron detector materials; direct conversion neutron detectors; He-3 gap replacement detectors; III-V semiconductors; neutrons; electrons; transport properties; electrical resistivity