Signature of Misoriented Bilayer Graphenelike and Graphanelike Structure in the Hydrogenated Diamond-Like Carbon Film

Abstract

In the present experimental work, we have described the signature of misoriented bilayer graphenelike and graphanelike structure in the hydrogenated diamond-like carbon film having interlayer disorder region and high specific surface area. Our new results have implications for bilayer graphene/graphane electronic devices.Index Terms-Graphane, graphite, high-field-effect mobility, hydrogenated diamond-like carbon (HDLC), interlayer disorder, misoriented bilayer graphene, Raman spectroscopy.

Atomic Hydrogen Storage in a Two-Dimensional Hydrogenated Diamond-Like Carbon Film

“…Due to existence of interlayer disorder, the layers of HDLC film stay perfectly parallel but their mutual orientation in the direction of planes is random and hence the 3D crystallinity of the HDLC films should be lost, while only the 2D crystallinity should be preserved 18 . These results imply two-dimensional behaviour of each layer of a typical HDLC film, also known as 2D-HDLC films 16,17 . Three representative electron energy loss (EEL) spectra at the carbon K-edge of 2D-HDLC film in cross-section geometry were examined at different depths of the film by a high resolution transmission electron microscope (HRTEM; JEOL-EM-2010; with LaB 6 emitter) operating at 200 kV.…”

“…Figure 2 provides a typical view of HDLC films onto Si substrate. Detailed characterization confirmed the existence of misoriented bilayer graphene-like (sp 2 C=C) and graphane-like (sp 3 C-H) structures in the HDLC films, having interlayer disorder 16,17 . Due to existence of interlayer disorder, the layers of HDLC film stay perfectly parallel but their mutual orientation in the direction of planes is random and hence the 3D crystallinity of the HDLC films should be lost, while only the 2D crystallinity should be preserved 18 .…”

“…Thus, the EEL spectra also confirm hexagonal crystallinity at different depths of the typical 2D-HDLC film (Figure 2). The aim of the present communication is a critical evaluation of the 2D-HDLC film as a system for storage of atomic hydrogen [14][15][16][17] . The basic condition for the realization of hydrogen storage material for practical uses is that it should be reversible, i.e.…”

“…It has been found that desorption energy 21 of hydrogen atoms is largest in graphane (C : H=1), being a saturated hydrocarbon 21 and that depends upon the degree of hydrogenation in the partially hydrogenated graphene (C : H > 1), being an unsaturated hydrocarbon. Thus the hydrocarbon thin film made in the present author's laboratory 17 , having interlayer disorder and consisting of graphane-like and graphene-like structures in each layer of the film, may be considered as partially hydrogenated graphene and this material should be suitable for atomic hydrogen (H) storage 1 . Due to the stable structure and small size of graphane, it has been estimated that molecular hydrogen (H 2 ) can be stored if graphane is doped with alkaline earth metals (AEMs) 22,23 .…”

“…Due to the stable structure and small size of graphane, it has been estimated that molecular hydrogen (H 2 ) can be stored if graphane is doped with alkaline earth metals (AEMs) 22,23 . In this respect, 2D-HDLC film, containing graphane-like structure should be suitable for doping with AEMs followed by hydrogen storage in molecular form 17 . In the earlier study 24 , the concentration of bonded hydrogen atoms in HDLC films under different deposition conditions was measured (by visible Raman spectroscopy) to be in the range 26-36 at%.…”