Scalable Flexible Patterned Graphene Gate TMD Biosensors

Two-dimensional transition metal dichalcogenides, such as MoS₂ and WS₂, have been shown to be promising materials for use in bio-sensing due to favorable electrical and mechanical properties. I will present our work on the fabrication of scalable flexible MoS₂ field effect transistor with patterned graphene back-gate. Flexible devices were fabricated on a Kapton substrate and incorporating graphene as the back-gate material due to its biocompatibility and its favorable physical properties. Monolayer MoS₂ single-crystal flakes were grown over a large area by chemical vapor deposition and then transferred onto a pre-patterned electrode array, resulting in a device yield > 70%, an average mobility of 10 cm²V^-1s^-1 and very low hysteresis. Flexibility tests confirm the flexible nature of the device when bent several hundred times. To create nano-biosensors, the surface of the MoS2 was functionalized via a re-engineered mu-opioid receptor and the devices were tested against opioid solutions of various concentrations. This work provides a pathway for the integration of MoS2 and other TMDs onto flexible/wearable/implantable devices used for trace detection of opioids or other chemicals.