From electroburning to sublimation: substrate and environmental effects in the electrical breakdown process of monolayer graphene

Abstract

We report on the characterization of the electrical breakdown (EB) process for the formation of tunneling nanogaps in single-layer graphene. In particular, we investigated the role of oxygen in the breakdown process by varying the environmental conditions (vacuum and ambient conditions). We show that the density of oxygen molecules in the chamber is a crucial parameter that defines the physical breakdown process: at low density, the graphene lattice is sublimating, whereas at high density, the process involved is oxidation, independent of the substrate material. To estimate the activation energies of the two processes, we use a scheme which consists of applying voltage pulses across the junction during the breakdown. By systematically varying the voltage pulse length, and estimating the junction temperature from a 1D thermal model, we extract activation energies which are consistent with the sublimation of graphene under high vacuum and the electroburning process under air. Our study demonstrates that, in our system, a better control of the gap formation is achieved in the sublimation regime.

Controlled, Low‐Temperature Nanogap Propagation in Graphene Using Femtosecond Laser Patterning

“…To interpret the experimental results, it is important to look into the underlying mechanisms ruling electroburning in graphene. Nanogap formation in graphene via electroburning in air is known to be oxidation‐driven . In a furnace, graphene oxidates homogeneously at temperatures above 300 °C …”

Massive Dirac Fermion Behavior in a Low Bandgap Graphene Nanoribbon Near a Topological Phase Boundary

“…Chemical vapor deposition‐grown graphene (Graphenea) was transferred on top and patterned into 400 nm wide stripes using reactive ion etching (Ar/O 2 ) after another step of e‐beam lithography. Sub‐5 nm gaps were formed in the graphene stripes using the electrical breakdown technique 22,23. Before transferring the ribbons, the graphene gaps were electrically characterized to ensure successful gap formation (see Figure S13, Supporting Information).…”

“…This allows a “GNRs‐last” fabrication process that avoids additional processing steps with the potential to introduce defects in the transferred pGNRs films (see Methods). Nanogaps are formed by electrical breakdown of a 400 nm wide‐pre‐patterned graphene channel, resulting in electrode separations of only a few nanometers 22,23. As the nanogap size is smaller than the average length of straight ribbon segments (Figure 1c), this allows us to probe transport properties we deem to be representative of the intrinsic ribbon properties.…”

Graphene wrinkle effects on molecular resonance states

“…The origin of these defects 6,7 and their effects on the mechanical [8][9][10] and electrical properties [11][12][13] of graphene are currently being investigated as graphenebased materials progress towards a technological stable state, reflected in the recent surge in patent applications. 14 In particular, graphene electrodes integrated in nanoscale devices serve as electrical contacts such as top-electrodes in organic solar cells, 15 bottom-electrodes in flexible electronics 16,17 and in-plane electrodes 18,19 in atomic 20 and single-molecular circuits. 21 Some commonly used techniques to obtain high-quality graphene include mechanical exfoliation, 22 epitaxial growth, 23 atomically clean graphene grown directly on single crystalline silver, 24,25 CVD growth on untreated copper foils 18,19,26 and on electropolished Cu.…”

“…14 In particular, graphene electrodes integrated in nanoscale devices serve as electrical contacts such as top-electrodes in organic solar cells, 15 bottom-electrodes in flexible electronics 16,17 and in-plane electrodes 18,19 in atomic 20 and single-molecular circuits. 21 Some commonly used techniques to obtain high-quality graphene include mechanical exfoliation, 22 epitaxial growth, 23 atomically clean graphene grown directly on single crystalline silver, 24,25 CVD growth on untreated copper foils 18,19,26 and on electropolished Cu. 27 The exfoliation method involves peeling few-layer graphene films from a piece of graphite.…”