Influence of Film Thickness on Nanofabrication of Graphene Oxide

Abstract

Nanofabrication of two-dimensional materials through mechanical machining is normally influenced by not only process parameters such as load and velocity but also intrinsic properties such as strength and thickness. Herein, we examined the effects of graphene oxide (GO) film thickness on nanofabrication on the plane surfaces and at the step edges using scanning probe microscope lithography. The material removal of GO initiates at the load above a critical value, which strongly depends on film thickness and locations. With the increase in film thickness, the critical load decreases monotonically on the plane surfaces but increases gradually at the step edges. Further, the critical load for the GO monolayer at the step edges is at least 25 times lower than that on the plane surfaces, and the gap decreases to around 3 times when GO thickness increases to four layers. Then, mechanical nanofabrication initiating from the GO step edge allows producing various nanopatterns under extremely low loads around 1 nN. Finally, the GO nanostructures are deoxidized by annealing at 800 °C in high-purity argon to restore their highly functionalized conjugated structures, which are supported by X-ray diffraction and Raman characterizations. This work provides a novel approach to fabricating graphene-like nanostructures by deoxidizing GO after nanofabrication, which holds significant potential for applications in graphene-based devices. Graphical Abstract

Thickness measurement of thin films using atomic force microscopy based scratching

“…Still, in the case of continuous layers (typically grown by chemical vapor deposition), it is necessary to make an exposed edge by AFM scratching. This is feasible in the case of grapheneoxide [101] or two-dimensional phyllosilicates (typically for mica, talc and pyrophyllite) [102,103], which are soft and have a low tensile strength. On the other hand, most studied two-dimensional materials such as graphene, hexagonal boron nitride and the family of transition-metal dichalcogenides are associated with very strong in-plane bonds and consequently with an ultimate tensile strength.…”

Saturable absorption properties of mixed lead-tin halide perovskites and their application in near-infrared ultrafast lasers

“…BPs synthesized by traditional methods are easily oxidized and degraded by air with poor stability [22]. GOs, exhibiting comparable properties such as broadband and ultrafast recovery saturable absorption, offer an alternative in this context [17,18], but the precise control of their layer thickness necessitates sophisticated fabrication processes [23]. And Pdots require complex tuning in broadband operation [24].…”