Detectors based on epitaxial boron nitride based on ¹⁰B isotope.

Boron nitride (BN) is a new emerging wide bandgap (Eg ~ 6 eV) semiconductor material that is promising for many applications due to its high thermal and chemical stability. Isotopically pure ¹⁰B BN is a promising platform for solid-state neutron detectors due to the very large thermal-neutron capture cross-section of ¹⁰B (σ ≈ 3840 b) [1], which warrants high sensitivity.

For this work boron nitride layers were grown by Metal Organic Vapour Phase Epitaxy. Triethylboron either based on natural B or based on ¹⁰B isotope were used as precursors for growth of natural BN or ¹⁰BN.

A few complementary detection schemes are possible using ¹⁰BN. In the scintillation mode, BN emits UV photons upon neutron or ion excitation. In reaction triggered by thermal neutrons it can emit α particles, which we can detect using a silicon diode. In parallel, we pursue an electrical approach, motivated by earlier BN-based devices [2] and developed here using impurity doping. BN shows high chemical robustness, and it is also resistant to neutron and γ irradiation, what underscores its suitability for harsh-environment applications. The demonstrated optical or electrical response indicates that ¹⁰BN can serve as a dual-mode platform for next-generation neutron detector technologies.

[1] V.F. Sears, Neutron News 3, 26–37 (1992).

[2] Z. Alemoush et al., Appl. Phys. Lett. 122, 012105 (2023).