▎ 摘　　要

NOVELTY - Preparation of graphene involves providing a substrate in a chemical deposition chamber which has a surface (S1), subjecting the substrate to thermal pretreatment while feeding at least one gaseous or supercritical oxidant into the chamber to bring the surface (S1) into contact with the oxidant and obtain a pretreated surface (S2), preparing graphene on the pretreated surface (S2) by chemical deposition. USE - Preparation of graphene (claimed) used as exciting material e.g. transparent flexible conducting electrodes, gas sensing, and post complementary metal-oxide semiconductor electronic devices. Uses include but are not limited to capacitors, field effect transistors, organic photovoltaic devices, organic light-emitting diodes, photo detectors, electrochemical sensors and energy-storing devices e.g. super capacitors, batteries and fuel cells. ADVANTAGE - The method enables preparation of graphene with improved quality and improved safety. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) device comprising graphene; and (2) use of gaseous or supercritical oxidant for thermal pretreatment of a substrate in a chemical deposition chamber.