Recent Development of Boron Nitride towards Electronic Applications

Boron nitride occurs in several polymorphs, among which cubic and hexagonal varieties have been extensively studied over many years and have found numerous practical applications. Although various forms of BN have been used as lubricant and abrasive material for many years, the unique electronic properties of BN have not been yet utilized. Due to their wide optical bandgaps (the widest among nitride semiconductors), cubic and hexagonal polymorphs of BN are promising candidates for optoelectronic devices operating in the deep-ultraviolet range and for high-power electronic devices for switching and radio-frequency applications. The layered structure of hexagonal BN allows preparation of ultrathin nanosheets with very smooth surfaces and low defect density, which are proved to be useful as supporting substrates and gate dielectric layers in graphene-based structures. The first device demonstrations are very encouraging. In this contribution, the recent progress in properties, fabrication technologies, and emerging applications of BN as a wide-gap semiconductor material is reviewed.