Study of Boron Nitride as Functional Materials Obtained under High Pressure and High Temperature

Abstract

Hexagonal boron nitride (hBN) and cubic BN (cBN) are known as heat-resistant materials and super-hard materials respectively. Some progresses in the synthesis of high purity BN crystals were achieved by using Ba-BN as a growth solvent material exhibiting BN's band-edge natures (cBN E_g=6.2 eV and hBN E_g=6.4 eV). By reducing oxygen and carbon impurities, an attractive potential of hBN as a deep ultraviolet (DUV) light emitter and also superior properties as substrates of graphene devices were realized. Our experimental study on BN crystals with respect to their phase transformation behavior and impurity control is reviewed.