▎ 摘　　要

NOVELTY - A molecular device preparing method involves preparing graphene transistor device array, where graphene transistor device array comprises each graphene transistor device with a gate electrode, a source electrode, a drain electrode and a conductive channel, the conductive channel is graphene, which is provided with a channel by the electron beam lithography and oxygen plasma etching to obtain a graphene channel, the graphene channel is provided with a nano-gap, followed by arranging a DNA sequence connecting part on the graphene channel. USE - Method for preparing molecular device for use in electrical signal detection. ADVANTAGE - The method enables preparing molecular device without surficial biomolecules and with improved detection accuracy. DETAILED DESCRIPTION - A molecular device preparing method involves preparing graphene transistor device array, where graphene transistor device array comprises each graphene transistor device with a gate electrode, a source electrode, a drain electrode and a conductive channel, the conductive channel is graphene, which is provided with a channel by the electron beam lithography and oxygen plasma etching to obtain a graphene channel, the graphene channel is provided with a nano-gap with length of 1-10 nm, followed by arranging a DNA sequence connecting part on the graphene channel. The DNA sequence connecting part is connected with the source electrode and the drain electrode in the graphene transistor device in a perpendicular direction. The graphene transistor device array is soaked in polyethylene glycol octyl phenyl ether for 0.5-3 hours, followed by activating terminal carboxyl group of graphene on both sides of the array, and connected DNA sequence-I or II into the nano-gap to obtain graphene-based electrodes molecular devices, where the DNA sequence-I is test organisms with small molecules interacting with the end of the modified DNA sequence by amino, and the DNA sequence-II is test organisms with small molecules interacting with connecting end of amino-modified DNA sequence of organic molecules.