Femtosecond laser assisted selective patterning of indium-tin-oxide thin film deposited on flexible polymer

Abstract

Finding ways to pattern indium-tin-oxide (ITO) thin films attached with flexible polymer plays an important role in manufacturing a large variety of photonic/optical devices including flexible display panels. This paper demonstrates femtosecond laser assisted selective removal of a thin layer of ITO coating deposited on a flexible polymer substrate. We utilize both flat-top and Gaussian shape beams to pattern micro/nano-metric grooves on ITO thin films disallowing any damage on the polymer substrate. The flat-top beam enables us to print rectangular profile grooves on ITO-coated polymer substrate. We also investigate the influence of objective lens and galvanometer scanner on the size and shape of the grooves on ITO thin films. Furthermore, we determine the ablation thresholds for selective patterning of ITO coating under various irradiation conditions. In addition, we achieved nano-grooves of width down to 570 nm, which has been reported for the first time in this paper. The engraved micro/nano-scale grooves on OTO thin films show excellent electrical isolation from the remaining ITO thin film. The femtosecond laser assisted fabrication technology exhibits a unique scheme for machining numerous patterns on ITO thin films with great flexibility. (C) 2015 Elsevier GmbH. All rights reserved.