Picosecond laser-direct fabrication of graphene-based electrodes for a gas sensor module with wireless circuits

This paper proposes an ultrafast-laser process for ablating multilayer graphene film to form the conductive electrodes for a gas sensor module with wireless circuits. In this study, a picosecond laser source was directly used to perform double scanning for precisely fabricating the spiral electrode pattern as the sensing test region. The ablated surface of multilayer graphene structures fabricated using sufficiently strong pulses with a pulse width of 7 ps and a wavelength of 532 nm was investigated through scanning electron microscopy. The graphene-based electrode was integrated with wireless circuits to form a gas sensor module. The relationship between the spiral electrode design and sensitivity to gas detection was analyzed. Electrical detection of gas was studied by employing different electrode designs, and change in the detection limit at room temperature with change in resistance was examined. Furthermore, the role of graphene-based devices comprising spiral electrodes fabricated using the laser process and integrated with wireless circuits to form a module in gas detection was analyzed.