▎ 摘　　要

NOVELTY - The method involves preparing a graphene oxide thin film. The graphene oxide thin film is reduced at a temperature of 1050 degrees C by a carbon containing gas atmosphere. A portion of graphene oxide flake is overlapped with the graphene oxide thin film. The carbon containing gas is formed from a mixture of ethanol, an acetylene and water vapor, a mixture of ethanol and water vapor, or a mixture of an acetylene, ethanol and water vapor. The flow ratio of the carbon containing gas and carrier gas is set to 1:500 and 1:5000. USE - Method for manufacturing graphene thin film used in electronic device of sensor (all claimed) e.g. biosensor used in pharmaceutical field and diagnostic medical field. ADVANTAGE - The mobility, electrical conductivity and electrical property of the graphene thin film are improved. The manufacturing process of graphene thin film is simplified and the manufacturing cost is reduced. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for an electronic device which includes a FET. The carrier mobility is set to more than 100 cm2/Vasterisks, by having a predetermined hole measurement. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the biosensor. Substrate (1) Graphene thin film (2) Source electrode (3) Drain electrode (4) Gate electrode (13)