Metalorganic chemical vapor deposition of hexagonal boron nitride on (001) sapphire substrates for thermal neutron detector applications

• Published in: Vacuum Vol. 137; pp. 81 - 84
• Main Authors: Ahmed, K., Dahal, R., Weltz, A., Lu, James J.-Q., Danon, Y., Bhat, I.B.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2017
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2016.12.023

This paper reports on the growth and characterization of hexagonal boron nitride (hBN) and its use for solid-state thermal neutron detection. The hBN epilayers were grown by metalorganic chemical vapor deposition on sapphire substrates at a temperature of 1350 °C. X-ray diffraction peak from the (002) hBN plane at a 2θ angle of 26.7° exhibited the c-lattice constant of 6.66 Å for these films. A strong peak corresponding to the high frequency Raman active mode of hBN was found for the films at 1370.5 cm-1 hBN-based solid-state neutron detectors were fabricated and tested with a metal-semiconductor-metal configuration with an electrode spacing of 1 mm and hBN thickness of 2.5 μm. Fabricated detectors showed strong response to deep UV light as well. An intrinsic thermal neutron detection efficiency of 0.86% was measured, which is close to the theoretically expected efficiency of 0.87%. These results demonstrate that epitaxial hBN films are promising for thermal neutron detection applications. •hBN films exhibited a c-lattice constant of 6.66 Å and a Raman peak at 1370.5 cm−1.•A detector was fabricated with 2.5 μm thick hBN with complete dry processing.•The detector showed strong deep UV and thermal neutron response.•Estimated intrinsic neutron detection efficiency, η of the detector is 0.86%.•η is very close (∼98%) of theoretical η of such thick hBN.