Epitaxial growth of continuous hexagonal boron nitride monolayer consisting of millimeter-size single crystal domains*

Epitaxial hexagonal boron nitride (h-BN) two-dimensional thin films with large single-crystal domains can significantly reduce density of grain boundaries and improve the device performance. In this work, we report the growth of continuous h-BN monolayer with millimeter-size epitaxial single-crystal domains on carburized Ni substrates by treating Ni with acetylene prior to the growth of h-BN in a plasma-assisted MBE system. We show that the dissolution of carbon can help achieve exclusive h-BN monolayer. In addition, we systemically study the effect of different temperatures and carburization conditions on the morphology of h-BN films. Through the optimization of the growth parameters, single crystal domains on the order of 0.6 mm are achieved. Furthermore, centimeter-scale alignment of these h-BN domains has been observed. Further Electron Backscatter Diffraction (EBSD) studies reveal the epitaxial relationship between h-BN domains and Ni substrate.