Enhanced Shubnikov–De Haas Oscillation in Nitrogen-Doped Graphene

Abstract

N-doped graphene displays many interesting properties compared with pristine graphene, which makes it a potential candidate in many applications. Here, we report that the Shubnikov-de Haas (SdH) oscillation effect in graphene can be enhanced by N-doping. We show that the amplitude of the SdH oscillation increases with N-doping and reaches around 5k Ω under a field of 14 T at 10 K for highly N-doped graphene, which is over 1 order of magnitude larger than the value found for pristine graphene devices with the same geometry. Moreover, in contrast to the well-established standard Lifshitz-Kosevich theory, the amplitude of the SdH oscillation decreases linearly with increasing temperature and persists up to a temperature of 150 K. Our results also show that the magnetoresistance (MR) in N-doped graphene increases with increasing temperature. Our results may be useful for the application of N-doped graphene in magnetic devices.

Electron–Hole Symmetry Breaking in Charge Transport in Nitrogen-Doped Graphene

“…[22][23][24][25][26][27][28] However, the achieved N-doped graphene often shows a rather low carrier mobility compared with pristine graphene. [22][23][24][25][26][27][28][29] Here, it still remains as a challenging task to achieve N-doped graphene with controlled doping type and doping level and with a desired high carrier mobility.Recently, we have succeeded in synthesizing large scale substitutional graphitic N-doped 4 graphene with an ultra-high carrier mobility by means of chemical vapor deposition (CVD). 30 In this work, we report on an investigation of electron transport properties of our high-quality, graphitic N-doped graphene by electrical and magnetotransport measurements.…”

“…The XPS spectra show only one N 1s peak centred at 401.0 eV in each graphene sample, suggesting that there is only one N lattice configuration, i.e., the substitutional doping type of N atoms (graphitic configuration), in the graphene samples. 28 Moreover, by taking the area ratio of the N 1s and C 1s peaks (the latter not shown here) after considering the atomic sensitivity factors, the atomic doping level can be estimated to be from 0.5% in the graphene sample grown at 1000 o C to 2.0 % in the graphene sample grown at 900 o C (Figure 1a and Figure S1a The observed uniform Raman D-band intensity over the entire Hall bar indicates a largescale dopant homogeneity in the N-doped graphene sample. Figure 1d shows the longitudinal resistance measured as a function of gate voltage for an N-doped graphene sample with the N atomic concentration of 2% at both room temperature and 1.9 K. From the transfer characteristic curves, we can extract the carrier mobility in the graphene sample.…”

“…[22][23][24][25][26][27][28] However, the achieved N-doped graphene often shows a rather low carrier mobility compared with pristine graphene. [22][23][24][25][26][27][28][29] Here, it still remains as a challenging task to achieve N-doped graphene with controlled doping type and doping level and with a desired high carrier mobility.…”

“…The well-defined quantum Hall plateaus ( Figure S2a) and Shubnikov-de Hass oscillations ( Figure S2b) are observed in the N-doped graphene sample, which further confirms the high mobility of our sample, compared to those 7 previously reported for N-doped graphene. [26][27][28] Figure 2a displays the conductivity measured as a function of back gate voltage Vg for N-doped graphene samples with three different N atomic concentrations at 1.9 K and zero magnetic field. In a graphitic N-doped graphene sample, an N atom serves as a donor and becomes positively charged after sacrificing an electron.…”

Berry phase shift from 2π to π in bilayer graphene by Li-intercalation and sequential desorption

“…The two-dimensional material which has high mobility like graphene can be expected to show quantum oscillations such as a Shubnikov-de Haas (SdH) oscillation [20][21][22][23][24][25]. The results of SdH oscillation enable us to obtain the fundamental physical properties, such as the Berry phase, the cyclotron mass, the scattering time, and mobility.…”