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

TL;DR

This study demonstrates the growth of high-quality hexagonal boron nitride films via metalorganic chemical vapor deposition on sapphire, showing their potential for solid-state thermal neutron detection with near-theoretical efficiency.

Contribution

It reports the first epitaxial growth and characterization of hBN on sapphire for neutron detection, highlighting its promising application in this field.

Findings

hBN films exhibit a c-lattice constant of 6.66 Å and a Raman peak at 1370.5/cm.

Neutron detectors with 2.5 μm thick hBN show 0.86% efficiency, close to the theoretical 0.87%.

Detectors also respond strongly to deep UV light.

Abstract

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 2theta angle of 26.7 deg exhibited the c-lattice constant of 6.66 {\AA} 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. 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 micron. 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.