catalyst-free growth of graphene, hexagonal boron nitride and their heterostructures

Abstract

Graphene and hexagonal boron nitrde(hBN) vertical heterostructure was grown using catalyst-free chemical vapor deposition techinique. Graphene and hBN were grown on hBN and graphene respectively, and graphene/hBN and hBN/graphene structures were obtained. The effect of growth conditions has been studied. The films were characterized with FE-SEM, Raman spectroscopy and TEM. Graphene islands or 3-dimensional nanostructure were grown on hBN flakes depending on the growth conditions. G-peak and 2D-peak were shown on the Raman spectrum obtained from the graphene grown hBN flakes. hBN film or 3-dimensional nanostructures were grown on exfoliate graphite and CVD graphene layers. The morphology was changed from film to 3-dimensional nanorods depending on the growth conditions. On the Raman spectrum, hBN peak was observed in addition to graphene peaks. Based on the growth conditions developed for Graphene/hBN and hBN/graphene growth structures, hBN / graphene / hBN vertical heterostructure was attempted to be grown by sequential growth of graphene and hBN on hbN flake. The growth of film was confirmed with FE-SEM and Raman spectroscopy. Analyzing microstructure with HR-TEM, The lattice constant of film covering the surface was same with hBN and Moire pattern was observed from the film grown on hBN flake.