Carrier Density and Electric Field Dependent Nonlinear Transport of Chemical Vapor Deposition Graphene

Abstract

We report on the measurements of nonlinear current-voltage characteristics of graphene fabricated by chemical vapor deposition. The current-voltage characteristic is described by a power law with a superlinear dependence of the current on the voltage, and the nonlinearity depends on the carrier density and the excitation level. The nonlinearity is strongest at the Dirac point and becomes weaker as the carrier density increases. At the Dirac point, we also observe a crossover to a much stronger nonlinear transport when the electric field increases above 104 V/m.

The Nonlinear Electronic Transport in Multilayer Graphene on Silicon-on-Insulator Substrates

“…[13] and such a high value of 𝛼 (close to 1.5) is consistent with the prediction of Schwinger's mechanism. [13,14,18,19] For the MLG channel between electrodes 3 and 4, using the parallel capacitor model, the strength of the electric field that corresponds to the on-start of the increase of 𝛼 is calculated to be 5 × 10 4 V/m, also consistent with the theoretical prediction. [13,19] It is worth mentioning that in the low bias regime (𝑉 < 0.1 V), the device exhibits feeble nonlinearity as well.…”

“…Another reason is the Zener-Klein tunneling effect, where carriers tunnel from the valence band to the conduction band through interband transition at low bias owing to the linear dispersion relationship of graphene and the absence of energy gap band. [19] In summary, we have obtained that MLG channels that partially or completely locate on ICP-etched silicon exhibit superlinear transport behavior. By fabricating MLG channels on SOI and Si/SiO 2 substrates, we obtain that this superlinearity results from the interaction between the MLG sheet and the ICP-etched silicon rather than the transfer process or the fabrication technique.…”

“…[13] The hallmark of this mechanism is that there is a crossover region from linear to superlinear 067201-2 behavior, where 𝛼 increases rapidly from 1.0 up to 1.5 when the strength of the electric field is higher than a critical value. [13,18,19] Using the Landau-Zener model, the critical electric field 𝐸 c is determined by…”

Multi-frequency sound production and mixing in graphene

“…The origin of R 2 ( V g ) is not important for the present discussion. (Various types of nonlinear behaviour have been predicted 32 – 34 and observed 17 , 35 – 37 ). The significance here is that R 2 is finite and increases in magnitude as the gate voltage approaches the Dirac point.…”