Bandgap opening in graphene induced by patterned hydrogen adsorption

Abstract

Graphene, a single layer of graphite, has recently attracted considerable attention owing to its remarkable electronic and structural properties and its possible applications in many emerging areas such as graphene-based electronic devices. The charge carriers in graphene behave like massless Dirac fermions, and graphene shows ballistic charge transport, turning it into an ideal material for circuit fabrication. However, graphene lacks a bandgap around the Fermi level, which is the defining concept for semiconductor materials and essential for controlling the conductivity by electronic means. Theory predicts that a tunable bandgap may be engineered by periodic modulations of the graphene lattice, but experimental evidence for this is so far lacking. Here, we demonstrate the existence of a bandgap opening in graphene, induced by the patterned adsorption of atomic hydrogen onto the Moiré superlattice positions of graphene grown on an Ir(111) substrate.

Structural Defects in Graphene

“…When graphene is covered more or less uniformly with hydroxyl or carboxyl groups, the material is called graphene oxide, which is essentially a highly defective graphene sheet functionalized with oxygen groups. 95 Plasma treatment and adsorption of atomic hydrogen on a graphene surface followed by its self-organization and hydrogen island formation 96 can also be referred to in the context of graphene treatment by chemical methods.…”

Janus graphene from asymmetric two-dimensional chemistry

“…Physisorption of chemical species on graphene would provide a facile way to alter its electronic properties 12 , however, covalent chemical modification shows a great advantage in achieving permanent stabilisation for long-term usage 13 . Previous attempts towards fundamental research on covalent functionalisation of graphene mainly involved the development of new modification strategies (for example, hydrogenation [14][15][16][17] , fluorination [18][19][20] , chlorination 21,22 , diazotization [23][24][25][26][27] and other cycloaddition reactions [28][29][30][31] ), covalent addition of edge and defects 27,32 , fabrication of chemical superlattices 26,33 and quantum effects in graphene modification 17,34 . Of the various significant research activities on graphene chemistry that have been conducted, nearly no work to date has been focused on the asymmetric chemistry of this ideal 2D atomic crystal via covalently attaching different functional groups on its two faces simultaneously.…”

Cooperative Interplay of van der Waals Forces and Quantum Nuclear Effects on Adsorption: H at Graphene and at Coronene

“…Hydrogen adsorption on carbon based materials such as graphite and graphene is relevant to hydrogen storage, 9 band gap engineering, [10][11][12][13] and potentially as the first step in H 2 formation in the interstellar medium. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] Although there is enormous interest in H adsorption on carbonaceous surfaces, with graphene, graphite and polycyclic aromatic hydrocarbons (PAHs) being the most widely studied model systems, we still don't fully understand the seemingly simple process of how a single H atom adsorbs on the surface.…”