Graphene photo detector with integrated waveguide biochemical sensors

In this study, we demonstrate the fabrication of a graphene integrated waveguide device with graphene as the photo detector for bio-chemical sensor applications. The working principle of the sensor is based on the variation of the local evanescent wave intensity according to the variation of the analyte's refractive index. Graphene film is transferred onto the field-effect transistor device, and an overlay of polydimethylsiloxane (PDMS) is used as the waveguide. A few microliter drop of glucose is placed on the PDMS waveguide, and the change in the photocurrent through the graphene is monitored. Depending of the refractive index of the glucose (or analyte) changed, the local evanescent field changed and hence the photo current of the graphene. We believe that this sensing platform can be used for detection of various bio-analytes and for bio reactions.