Metal-semiconductor- metal neutron detectors based on hexagonal boron nitride epitaxial layers

Hexagonal boron nitride (hBN) possesses extraordinary potential for solid-state neutron detector applications. This stems from the fact that the boron-10 (B-10) isotope has a capture cross-section of 3840 barns for thermal neutrons that is orders of magnitude larger than other isotopes. Epitaxial layers of hBN have been synthesized by metal organic chemical vapor deposition (MOCVD). Experimental measurements indicated that the thermal neutron absorption coefficient and length of natural hBN epilayers are about 0.0036 mu m(-1) and 277 mu m, respectively. To partially address the key requirement of long carrier lifetime and diffusion length for a solid-state neutron detector, micro-strip metal-semiconductor-metal detectors were fabricated and tested. A good current response was generated in these detectors using continuous irradiation with a thermal neutron beam, corresponding to an effective conversion efficiency approaching similar to 80% for absorbed neutrons.