Graphene gas sensor and preparation method thereof

The embodiment of the invention discloses a graphene gas sensor and a preparation method thereof. The preparation method comprises the following steps: sequentially deposing a sacrificial layer and a strain membrane on a substrate firstly, then directly preparing a graphene layer on the strain membrane, or transferring the prepared graphene layer onto the strain membrane, forming a mesa by virtue of lithography and corrosion, and meanwhile, exposing the sacrificial layer; then continuously deposing a metal electrode on the graphene layer; and finally, laterally corroding the sacrificial layer to enable the strain membrane to separate from the substrate and self curling to form a tube, and obtaining the curled graphene gas sensor which is adhered to the inner wall of the tube. The graphene gas sensor has high sensitivity to various gas molecules, has a three-dimensional structure, is small in device size, simple in preparation method and low in cost and is suitable for mass production. In addition, according to the graphene gas sensor disclosed by the embodiment of the invention, with the tubular structure with controllable diameter, a natural conveying channel for a gas to be detected is provided, and the tubular structure can also be integrated with other on-chip micro-nano function units to construct a chip laboratory.