  The growth of single-layer graphene (SLG) by chemical vapor deposition (CVD)
on copper surfaces is very popular because of the self-limiting effect that
prevents the growth of few-layer graphene (FLG). However, the reproducibility
of the CVD growth of homogeneous SLG remains a major challenge, especially if
one wants to avoid heavy surface treatments, monocrystalline substrates and
expensive equipment to control the atmosphere inside the growth system. We
demonstrate here that backside tungsten coating of copper foil allows the
exclusive growth of SLG with full coverage by atmospheric pressure CVD
implemented in a vacuum-free outfit. We show that the absence of FLG patches is
related to the absence of decomposition of methane on the backside and
consequently to the suppression of C diffusion through copper. In the
perspective of large-scale production of graphene, this approach constitutes a
significant improvement to the traditional CVD growth process since (1) a tight
control of the hydrocarbon flow is no longer required to avoid FLG formation
and, consequently, (2) the growth duration necessary to reach full coverage can
be dramatically shortened.
