High-temperature molecular beam epitaxy of graphene and hexagonal boron nitride
for potential layer release applications
T.S. Cheng1 , J. Wrigley1 , J. Bradford1 , T. James1 , J. Thomas1 , A. Summerfield1,
C. Elias2 , P. Valvin2 , T. Pelini2 , B. Gil2 , G. Cassabois2,
C.J. Mellor1 , A.N. Khlobystov3 , L. Eaves1 , C.T. Foxon1 , P.H. Beton1 , S.V. Novikov1,*
1 School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
2Laboratoire Charles Coulomb, CNRS-Université de Montpellier,34095, Montpellier, France
3 School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
*e-mail: Sergei.Novikov@nottingham.ac.uk
We will discuss growth of graphene and hexagonal boron-nitride (hBN) layers by high temperature molecular beam epitaxy (HT-MBE) at substrate temperatures between 1000oC and 1700oC. We have used different types of the carbon sublimation sources to grow graphene on SiC, sapphire and hBN substrates. We have demonstrated that aligned, lattice matched graphene can be grown by HT-MBE using hBN substrate temperatures in the range 1600−1700°C.
We have shown that HT-MBE at substrate temperatures of ~1400oC can achieve mono- and few-layer thick hBN with control of the hBN coverage and atomically flat hBN surfaces, which is essential for 2D applications of hBN layers. The hBN coverage can be reproducibly controlled by the growth time, substrate temperature and boron to nitrogen flux ratios.However, decreasing the epitaxy temperature below 1250oC, rapidly degrades the optical properties of the hBN layers.
Our work demonstrates a new high-temperature approach to the MBE growth of epitaxial graphene and boron nitride.