Electrical transport properties of hexagonal boron nitride epilayers

Due to its exceptional physical properties, including ultrahigh energy band gap, layered structure, strong optical transitions near the band-edge, high electrical resistivity, and large thermal neutron capture cross-section of the Boron isotope, Boron-10 (¹⁰B), hexagonal boron nitride (h-BN) has attracted a great deal of attention recently for its potential applications in deep UV (DUV) optoelectronics, single photon emitters and solid-state neutron detection. This chapter provides a brief overview on recent progresses made by the authors in the growth of freestanding h-BN epilayers with large thicknesses (up to 200 μm), understanding of vertical and lateral transport properties and realization of h-BN thermal neutron detectors with unprecedented detection efficiencies among solid-state detectors. These results have also identified basic material parameters which are key to further improve the transport properties and performance of h-BN devices. It is anticipated that further advances in material growth and novel device architecture designs will bring the developed h-BN neutron detector technology to the next level of maturity.