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Title: Hexagonal boron nitride neutron detectors with high detection efficiencies

Abstract

Here, neutron detectors fabricated from 10B enriched hexagonal boron nitride (h- 10BN or h-BN) epilayers have demonstrated the highest thermal neutron detection efficiency among solid-state neutron detectors to date at about 53%. In this work, photoconductive-like vertical detectors with a detection area of 1 × 1 mm 2 were fabricated from 50 μm thick free-standing h-BN epilayers using Ni/Au and Ti/Al bilayers as ohmic contacts. Leakage currents, mobility-lifetime (μτ) products under UV photoexcitation, and neutron detection efficiencies have been measured for a total of 16 different device configurations. The results have unambiguously identified that detectors incorporating the Ni/Au bilayer on both surfaces as ohmic contacts and using the negatively biased top surface for neutron irradiation are the most desired device configurations. It was noted that high growth temperatures of h- 10BN epilayers on sapphire substrates tend to yield a higher concentration of oxygen impurities near the bottom surface, leading to a better device performance by the chosen top surface for irradiation than by the bottom. Preferential scattering of oxygen donors tends to reduce the mobility of holes more than that of electrons, making the biasing scheme with the ability of rapidly extracting holes at the irradiated surface while leaving themore » electrons to travel a large average distance inside the detector at a preferred choice. When measured against a calibrated 6LiF filled micro-structured semiconductor neutron detector, it was shown that the optimized configuration has pushed the detection efficiency of h-BN neutron detectors to 58%. These detailed studies also provided a better understanding of growth-mediated impurities in h-BN epilayers and their effects on the charge collection and neutron detection efficiencies.« less

Authors:
 [1];  [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Texas Tech Univ., Lubbock, TX (United States)
Publication Date:
Research Org.:
Texas Tech Univ., Lubbock, TX (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1418973
Alternate Identifier(s):
OSTI ID: 1417780
Grant/Contract Number:  
NA0002927
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 123; Journal Issue: 4; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
61 RADIATION PROTECTION AND DOSIMETRY; solid-state neutron detectors; hexagonal boron nitride; wide bandgap semiconductors

Citation Formats

Maity, A., Grenadier, S. J., Li, J., Lin, J. Y., and Jiang, H. X.. Hexagonal boron nitride neutron detectors with high detection efficiencies. United States: N. p., 2018. Web. doi:10.1063/1.5017979.
Maity, A., Grenadier, S. J., Li, J., Lin, J. Y., & Jiang, H. X.. Hexagonal boron nitride neutron detectors with high detection efficiencies. United States. doi:10.1063/1.5017979.
Maity, A., Grenadier, S. J., Li, J., Lin, J. Y., and Jiang, H. X.. Tue . "Hexagonal boron nitride neutron detectors with high detection efficiencies". United States. doi:10.1063/1.5017979.
@article{osti_1418973,
title = {Hexagonal boron nitride neutron detectors with high detection efficiencies},
author = {Maity, A. and Grenadier, S. J. and Li, J. and Lin, J. Y. and Jiang, H. X.},
abstractNote = {Here, neutron detectors fabricated from 10B enriched hexagonal boron nitride (h-10BN or h-BN) epilayers have demonstrated the highest thermal neutron detection efficiency among solid-state neutron detectors to date at about 53%. In this work, photoconductive-like vertical detectors with a detection area of 1 × 1 mm2 were fabricated from 50 μm thick free-standing h-BN epilayers using Ni/Au and Ti/Al bilayers as ohmic contacts. Leakage currents, mobility-lifetime (μτ) products under UV photoexcitation, and neutron detection efficiencies have been measured for a total of 16 different device configurations. The results have unambiguously identified that detectors incorporating the Ni/Au bilayer on both surfaces as ohmic contacts and using the negatively biased top surface for neutron irradiation are the most desired device configurations. It was noted that high growth temperatures of h-10BN epilayers on sapphire substrates tend to yield a higher concentration of oxygen impurities near the bottom surface, leading to a better device performance by the chosen top surface for irradiation than by the bottom. Preferential scattering of oxygen donors tends to reduce the mobility of holes more than that of electrons, making the biasing scheme with the ability of rapidly extracting holes at the irradiated surface while leaving the electrons to travel a large average distance inside the detector at a preferred choice. When measured against a calibrated 6LiF filled micro-structured semiconductor neutron detector, it was shown that the optimized configuration has pushed the detection efficiency of h-BN neutron detectors to 58%. These detailed studies also provided a better understanding of growth-mediated impurities in h-BN epilayers and their effects on the charge collection and neutron detection efficiencies.},
doi = {10.1063/1.5017979},
journal = {Journal of Applied Physics},
number = 4,
volume = 123,
place = {United States},
year = {Tue Jan 23 00:00:00 EST 2018},
month = {Tue Jan 23 00:00:00 EST 2018}
}

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Works referenced in this record:

Self-powered micro-structured solid state neutron detector with very low leakage current and high efficiency
journal, June 2012

  • Dahal, R.; Huang, K. C.; Clinton, J.
  • Applied Physics Letters, Vol. 100, Issue 24, 243507
  • DOI: 10.1063/1.4729558