Raman scattering and electrical resistance of highly disordered graphene

Abstract

Raman scattering (RS) spectra and current-voltage characteristics at room temperature were measured in six series of small samples fabricated by means of electron-beam lithography on the surface of a large size (5x5 mm) industrial monolayer graphene film. Samples were irradiated by different doses of C${}^+$ ion beam up to $10^{15}$ cm${}^{-2}$. It was observed that at the utmost degree of disorder, the Raman spectra lines disappear which is accompanied by the exponential increase of resistance and change in the current-voltage characteristics.These effects are explained by suggestion that highly disordered graphene film ceases to be a continuous and splits into separate fragments. The relationship between structure (intensity of RS lines) and sample resistance is defined. It is shown that the maximal resistance of the continuous film is of order of reciprocal value of the minimal graphene conductivity $\pi h/4e^2\approx 20$ kOhm.Comment: 5 pages, 5 eps figures. As accepted for publication in PR

Influence of ageing on Raman spectra and the conductivity of monolayer graphene samples irradiated by heavy and light ions

“…At large L D (small Φ), the ratio I D /I G increases with decreasing L D , passes through a maximum and then rapidly decreases. Such non-monotonic behavior is common for many experimental observations [5][6][7][8][9] and agrees with the theoretical model 13 based on the assumption that a single ion impact leads to the formation of a defect characterized by two length scales r S and r A (r A > r S ), which are the radii of two circular areas surrounding the defect (see insert in Fig. 5).…”

Transferless Inverted Graphene/Silicon Heterostructures Prepared by Plasma-Enhanced Chemical Vapor Deposition of Amorphous Silicon on CVD Graphene

“…Due to the nature of our experiment, it was not possible to measure the electrical properties of the graphene itself because the particular level and type of disorder is achieved only after the deposition of Si, and its presence would, in turn, influence the measurement. However, there are numerous reports on the relation between I D /I G (or L D , n D ) and ρ (or sheet resistance, R S ) [32,33]. In stage 1, ρ ranges from ≈600 Ω of pristine CVD graphene to ≈ 20 kΩ [33].…”

Irradiation-induced broadening of the Raman spectra in monolayer graphene

“…For C + ions with M = 12 in atomic mass units (amu) and for Xe + ions (M = 131 amu) with E = 35 keV, k = 0.06-0.08 and 0.8 correspondingly [10]. The changes in the intensities of both D-and 2D-lines ID and I2D with increase of Nd in these samples were studied in [10][11][12]. It was shown that I2D continuously decreases, while ID first increases and then decreases, the maximal value is achieved at Nd ≈ 4x10 12 cm -2 , which corresponds to the mean distance between defects Ld ≈ (Nd) -1/2 ≈ 5 nm.…”