Single layer graphene film by ethanol chemical vapor deposition: Highly efficient growth and clean transfer method

摘要

The choice of ethanol (C2H5OH) as carbon source in the Chemical Vapor Deposition (CVD)udof graphene on copper foils can be considered as an attractive alternative among theudcommonly used hydrocarbons, such as methane (CH4) [1]. Ethanol, a safe, low cost and easyudhandling liquid precursor, offers fast and efficient growth kinetics with the synthesis of fullyformedudgraphene films in just few seconds [2]. In previous studies of graphene growth fromudethanol, various research groups explored temperature ranges lower than 1000 °C, usuallyudreported for methane-assisted CVD. In particular, the 650–850 °C and 900 °C ranges wereudinvestigated, respectively for 5 and 30 min growth time [3, 4]. Recently, our group reportedudthe growth of highly-crystalline, few-layer graphene by ethanol-CVD in hydrogen flow (1–ud100 sccm) at high temperatures (1000–1070 °C) using growth times typical of CH4-assistedudsynthesis (10–30 min) [5]. Furthermore, a synthesis time between 20 and 60 s in the sameudconditions was explored too. In such fast growth we demonstrated that fully-formed grapheneudfilms can be grown by exposing copper foils to a low partial pressure of ethanol (up to 2 Pa)udin just 20 s [6] and we proposed that the rapid growth is related to an increase of the Cuudcatalyst efficiency due weak oxidizing nature of ethanol. Thus, the employment of such liquidudprecursor, in small concentrations, together with a reduced time of growth and very lowudpressure leads to highly efficient graphene synthesis. By this way, the complete coverage of audcopper catalyst surface with high spatial uniformity can be obtained in a considerably lowerudtime than when using methane.