Graphitization and amorphization of textured carbon using high-energy nanosecond laser pulses
Tay, Beng Kang
Date of Issue2016
School of Electrical and Electronic Engineering
CNRS International NTU THALES Research Alliances
Laser pulses can effectively induce local structural changes and modify the physical properties of carbon allotropes. So far, only graphitization has been demonstrated using low laser energies (≤1 J/cm2). The novelty of this paper is a result of laser-induced amorphization of a highly anisotropic carbon allotrope by using high energy (1.5–15.4 J/cm2) 5 ns, 532 nm Nd-YAG laser pulses. Moreover, cycling phase change, between an amorphous and a crystalline phase, is also obtained by adjusting the pulse energy. However, cycling ability is restricted to a few cycles as a consequence of laser-induced surface damages caused by both high temperatures during and high thermal gradients during and after laser exposure. The occurrence of graphitization or amorphization depends on the amount of solid crystalline seeds during solidification from the melt, which is controlled by the post-pulse temperature of the carbon surface. This study uncovers new applications of carbon allotropes, such as optically-controlled reversible phase-change memories.
© 2016 Elsevier. This is the author created version of a work that has been peer reviewed and accepted for publication by Carbon, Elsevier. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1016/j.carbon.2016.04.026].