Realization of continuous Zachariasen carbon monolayer

Abstract

Rapid progress in two-dimensional (2D) crystalline materials has recently enabled a range of device possibilities. These possibilities may be further expanded through the development of advanced 2D glass materials. Zachariasen carbon monolayer, a novel amorphous 2D carbon allotrope, was successfully synthesized on germanium surface. The one-atom-thick continuous amorphous layer, in which the in-plane carbon network was fully sp 2 -hybridized, was achieved at high temperatures (>900°C) and a controlled growth rate. We verified that the charge carriers within the Zachariasen carbon monolayer are strongly localized to display Anderson insulating behavior and a large negative magnetoresistance. This new 2D glass also exhibited a unique ability as an atom-thick interface layer, allowing the deposition of an atomically flat dielectric film. It can be adopted in conventional semiconductor and display processing or used in the fabrication of flexible devices consisting of thin inorganic layers.

Universal behaviors in the wrinkling transition of disordered membranes

“…Among the numerous effects observed one finds: variation (increase or decrease) of electronic conductivity according to the size of the defects, increase of elasticity for moderate density of vacancies and decrease at higher density, decrease of thermal conductance, of fracture strength, enhancement of reactivity, appearance of ferromagnetism and so on [11][12][13][14][15]. As part of this defect engineering activity, a specific effort involving various experimental or numerical techniques -(low pressure) chemical vapor deposition [16], ion/electron irradiation [17][18][19][20][21][22] or molecular dynamic simulation [23][24][25] -has been made toward the design of defect-induced 2D amorphous counterparts of graphene and graphene-like materials. A highlight of this activity is the achievement by electron irradiation of a stepby-step, atom by atom, crystal-to-glass transition giving rise to a vacancy-amorphized graphene structure [16][17][18] similar to the continuous random network proposed by Zachariasen [26].…”

“…As part of this defect engineering activity, a specific effort involving various experimental or numerical techniques -(low pressure) chemical vapor deposition [16], ion/electron irradiation [17][18][19][20][21][22] or molecular dynamic simulation [23][24][25] -has been made toward the design of defect-induced 2D amorphous counterparts of graphene and graphene-like materials. A highlight of this activity is the achievement by electron irradiation of a stepby-step, atom by atom, crystal-to-glass transition giving rise to a vacancy-amorphized graphene structure [16][17][18] similar to the continuous random network proposed by Zachariasen [26]. Many characteristics of this transition have been determined: the onset of the defect-induced amorphization process, its temperature dependence, the structural response to vacancy insertion, the nature of the electronic density of states of the defective configurations [23], a transition in the fracture response from brittle to ductile when increasing vacancy concentration [27]; finally a careful analysis of the glassy-graphene structure in terms of a proliferation of non-hexagonal carbon rings has been performed [18,25].…”

Evidence of a two-dimensional glass transition in graphene: Insights from molecular simulations

“…Recent studies have successfully demonstrated the experimental realization of a Zachariasen carbon monolayer employing low-pressure chemical vapor deposition (LPCVD) 32 . Further, disordered graphene has been achieved using alternate methods such as CVD 33 , ion irradiation 16 , 34 , 35 and electron irradiation 36 , 37 .…”

Direct growth of graphene on Ge(100) and Ge(110) via thermal and plasma enhanced CVD

“…Similar to Cu, Ge exhibits a self-limiting effect resulting from the low carbon solubility in Ge 20 and thus, enables monolayer graphene synthesis 21 . The graphene flakes were reported to nucleate via covalent bonds at Ge dimer vacancies on a surface with (100) crystal orientation 22 .…”