MoS2 FET fabrication using adhesion lithography and their application to chemical sensors

Molybdenum disulfide (MoS2) field effect transistors (FETs) are investigated for chemical sensor applications. However, the formation of electrodes after a MoS2 transistor is transferred to the substrate results in process damage. In this work, MoS2 FETs are fabricated by implementing a gate, source, and drain pre-formation, and then by transferring MoS2 using polydimethylsiloxane. The fabricated FETs are characterized after their exposure to ethanol vapor as a case study for chemical sensor applications. A sub-threshold swing of 72 mV/dec can be observed for a fabricated FET with a field effect mobility of 5.05 cm2 V−1 s−1. The ON/OFF ratio is approximately 104. No significant change in the FET's properties due to contact resistance is observed. Next, Vth is shifted to a 1.7 V-positive value upon ethanol vapor exposure. By removing the ethanol vapor, a 1.4 V-negative shift in the threshold voltage value is observed compared with that before the ethanol vapor removal.