Fabrication Strategies and Measurement Techniques for Performance Improvement of Graphene/Graphene Derivative Based FET Gas Sensor Devices: A Review

In the ever-expanding arena of gas sensor research, graphene (or graphene derivative viz. reduced graphene oxide (rGO)) field-effect transistors (FET) are the most recent inclusions which have enormous potential to detect wide variety of oxidizing and reducing target species with high sensitivity. This review article aims to unify the various strategies adopted (during fabrication or during measurement) by the researchers to improve the performance index of graphene/rGO-FET gas sensor devices. These strategies can broadly be classified as; (i) fabrication/device level optimization and (ii) operational/measurement technique improvisation. In the first category, improvement of various sensing parameters of graphene/rGO FET through functionalization/surface modification/doping of channel, use of novel gate dielectric/ gate material and exploration of innovative device configurations (ionic top gate, single back gate or dual gate) have been discussed. While in the second category, optimized gate biasing, AC phase-sensitive measurement, quasi static/ real time conductance measurement and low-frequency noise spectra based measurement techniques have been elucidated. After critically comparing the performance improvement devoting the above two lines of approaches, with emphasis on the unique advantage and limitations of each of the schemes, the review concludes with the indication towards future research directions that lie ahead.