Synthesis of highly uniform monolayer graphene by etching the multilayer spots for electronic devices

We demonstrate a facile method to grow highly uniform monolayer graphene films on copper foils by atmospheric pressure chemical vapor deposition (APCVD). The technique in this method includes lowering flow ratio of methane/hydrogen and extending exposure time to hydrogen. All the multilayer islands will be etched away by hydrogen during this growth process, resulting in obtaining highly uniform monolayer graphene. A mechanism for the suppression of mutilayer spots based on the etching effect of hydrogen is proposed. The electron and hole room-temperature mobilities for the back-gated graphene transistors are up to about 3800 cm
²
V
^-1
s
^-1
and 3300 cm
²
V
^-1
s
^-1
, respectively.