Graphene sensor

1. A sensor, comprising:

a fluid channel defined in a substrate, the fluid channel having a first end and a second end;

a first cavity in communication with the first end of the fluid channel, and a second cavity in communication with the second end of the fluid channel opposite the first end so as to define a fluid flow path comprising the first cavity, the fluid channel and the second cavity;

a transistor gate dielectric layer, comprising a first dielectric layer, disposed on the substrate and over the fluid channel;

a graphene layer disposed on the transistor gate dielectric layer;

a second dielectric layer disposed on the graphene layer;

a source region disposed on the transistor gate dielectric layer, the source region also in contact with a first end of the graphene layer;

a drain region disposed on the gate dielectric layer, the drain region also in contact with a second end of the graphene layer;

a capping layer disposed on a portion of the substrate; and

wherein the channel comprises a physical opening formed in the substrate so as to define a gap between a bottom surface of the gate dielectric layer and a top surface of the substrate.

2. The sensor of claim 1 , wherein the sensor includes a gate region.

3. The sensor of claim 1 , wherein the graphene layer includes a graphene tube.

4. The sensor of claim 1 , wherein the second dielectric layer has a greater thickness than the first dielectric layer.

5. The sensor of claim 1 , wherein a longitudinal axis of the channel is orthogonal to an axis that connects the source and drain regions.