Picosecond laser micropatterning of graphene films for rapid heating chips

摘要

This research aims to pattern multilayer graphene films for rapid heating chips with a multichannel electrode structure and to investigate the interaction between picosecond pulsed green lasers and graphene films coated on glass substrates. The optimal laser direct writing conditions consisted of the laser fluence of 4.72 J/cm(2), the pulse repetition frequency of 300 kHz, the scanning speed of a galvano scanner of 1500 mm/s, the overlapping rate of laser spots of 66%, and parallel lines of the laser processing path with the line-scan spacing of 1 lm in one-cycle process to fabricate the graphene-based heating chips with multichannel electrode structures. The surface morphology, cross-sectional profile, current-voltage (I-V) curve, material characterization, and electric heating behavior on graphene/glass substrates were detected by a confocal laser scanning microscope, a Hall effect probing measurement system, a Raman spectroscopy, and a temperature recorder, respectively. The experimental results showed that the laser ablating depths increased from 9 lm to 14.2 lm when the overlapping rates of laser spots increased from 11% to 94%, respectively. Moreover, the electric heating results revealed that the temperature of graphene-based heating chips increased with increasing the applied DC voltage. The heating rate of 6 degrees C/s for laser-patterned graphene films was larger than that of 1.5 degrees C/s for unpatterned graphene films. In addition, the maximum heating temperature of laser-patterned graphene films with multichannel electrode structures was approximately 93.4 degrees C when the applied DC voltage was 25 V. (C) 2018 Elsevier B.V. All rights reserved.