Nutpool Materials

Research studies on the growth and properties of hexagonal boron nitride hBN have recently attracted a lot of attention. The lattice parameter of h-BN is very close to that of the recently discovered graphene. The surface of hBN is atomically flat and will provide an ideal chemically inert dielectric substrate for 2D-structures. Secondly, the band gap of h-BN is about 6 eV and that has fuelled the interest in hBN as a wide gap material for deep-ultraviolet device (DUV) applications. Currently there are world-wide attempts to develop a reproducible technology for the growth of large area h-BN layers by chemical vapour deposition (CVD), metal-organic chemical vapour deposition (MOCVD) and molecular beam epitaxy (MBE). We have recently demonstrated growth of hBN layers using MBE at extremely high growth temperatures from 1390o to 1690oC [1]. Atomic force microscopy (AFM) shows mono- and few-layer hBN island growth, while conducting atomic force microscopy demonstrates that the MBE grown hBN has electrical properties comparable to exfoliated hBN. The high optical quality of hBN grown at high temperatures on highly oriented pyrolytic graphite (HOPG) has been confirmed by both spectroscopic ellipsometry and photoluminescence spectroscopy [2]. In this work we present our recent results on the high-temperature MBE of hBN monolayers with atomically controlled thicknesses for 2D applications and on the growth of significantly thicker hBN layers for potential DUV applications.[1] Y.J. Cho, et al. Scientific Reports 6 (2016) 34474.[2] T. Q.P. Vuong, et al. 2D Materials 4 (2017) 021023.