Mesoscopic conductance fluctuations in multi-layer graphene

Chuang, Chiashain; Lin, Li-Hung; Aoki, Nobuyuki; Ouchi, Takahiro; Mahjoub, Akram M.; Woo, Tak-Pong; Puddy, R; Ochiai, Y.; Smith, C. G.; Liang, Chi‐Te

doi:10.1063/1.4816721

Cited by 12 publications

(8 citation statements)

References 72 publications

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“…5b) for the negative charge carrier density. This agrees well with previous reports for the general dependence and with respect to the saturation for temperatures below 10 K, which is attributed to either scattering from substrate impurities and air [44] or increased electron-electron interaction [40,45]. The different low-temperature-behavior depending on charge carrier type as highlighted in the inset indicates different scattering mechanisms on the electron and hole side of the Dirac point at low temperatures.…”

Section: Phase Coherence and Scattering Timessupporting

confidence: 92%

Impact of nitrogen doping on the band structure and the charge carrier scattering in monolayer graphene

Braatz

Veith

Köster

et al. 2021

Phys. Rev. Materials

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The addition of Nitrogen as a dopant in monolayer graphene is a flexible approach to tune the electronic properties of graphene as required for applications. Here, we investigate the impact of the doping process that adds N-dopants and defects on the key electronic properties, such as the mobility, the effective mass, the Berry phase and the scattering times of the charge carriers. Measurements at low temperatures and magnetic fields up to 9 T show a decrease of the mobility with increasing defect density due to elastic, short-range scattering. At low magnetic fields weak localization indicates an inelastic contribution depending on both defects and dopants. Analysis of the effective mass shows that the N-dopants decrease the slope of the linear bands, which are characteristic for the band structure of graphene around the Dirac point. The Berry phase, however, remains unaffected by the modifications induced through defects and dopants, showing that the overall band structure of the samples is still exhibiting the key properties as expected for Dirac fermions in graphene.

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Section: Phase Coherence and Scattering Timessupporting

confidence: 92%

Impact of nitrogen doping on the band structure and the charge carrier scattering in monolayer graphene

Braatz

Veith

Köster

et al. 2021

Phys. Rev. Materials

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“…Obviously, the graphene wide constriction region is revealed in bright color as shown in Figure 3(b). Interestingly, the enhancing and reducing conductance spots are not restricted to the wide constriction outline that was marked by white dashed line in Figure 3(c), and the hot current would suppress the conductance oscillations as previous reports [14,25,28]. Such LT-SGM conductance characteristics are typical evidences for quantum ring structures due to the lateral expanse of the tip perturbation as previous reports [13,14,29,30].…”

Section: Resultssupporting

confidence: 84%

High Current-Induced Electron Redistribution in a CVD-Grown Graphene Wide Constriction

Chuang

Woo

Liu

et al. 2016

Journal of Nanomaterials

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Investigating the charge transport behavior in one-dimensional quantum confined system such as the localized states and interference effects due to the nanoscale grain boundaries and merged domains in wide chemical vapor deposition graphene constriction is highly desirable since it would help to realize industrial graphene-based electronic device applications. Our data suggests a crossover from interference coherent transport to carriers flushing into grain boundaries and merged domains when increasing the current. Moreover, many-body fermionic carriers with disordered system in our case can be statistically described by mean-field Gross-Pitaevskii equation via a single wave function by means of the quantum hydrodynamic approximation. The novel numerical simulation method supports the experimental results and suggests that the extreme high barrier potential regions on graphene from the grain boundaries and merged domains can be strongly affected by additional hot charges. Such interesting results could pave the way for quantum transport device by supplying additional hot current to flood into the grain boundaries and merged domains in one-dimensional quantum confined CVD graphene, a great advantage for developing graphene-based coherent electronic devices.

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“…The conductance fluctuations are observed, and they decrease as L increase from L = 0.32 to 50 K, which are typical properties in disordered mesoscopic graphene [24][25][26][27]. at various driving currents from I = 20 nA to 30000 nA at a fixed L of 0.32 K, which reveals similar conductance fluctuation characteristics by current heating in the nonequilibrium regime due to the hot carrier effects in disordered two-dimensional systems [18,[28][29][30][31].…”

Section: Resultssupporting

confidence: 48%

“…In order to further discuss the linear relation between e and that indicates little carrier-phonon scattering in our sample A, we fabricate multilayer exfoliated graphene (sample B) that showed the same linear relation between e and by zero field resistance as a thermometer and conductance fluctuations due to its disordered property as in our previous reports [23][24][25][26]. Again, we are able to measure the conductance fluctuations for temperature and current dependence as shown in Figure 5(a) and inset [13].…”

Section: Resultsmentioning

confidence: 99%

Hot Carriers in CVD-Grown Graphene Device with a Top h-BN Layer

Chuang

Mineharu

Matsumoto

et al. 2018

Journal of Nanomaterials

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We investigate the energy relaxation of hot carriers in a CVD-grown graphene device with a top h-BN layer by driving the devices into the nonequilibrium regime. By using the magnetic field dependent conductance fluctuations of our graphene device as a self-thermometer, we can determine the effective carrier temperature e at various driving currents while keeping the lattice temperature L fixed. Interestingly, it is found that e is proportional to I, indicating little electron-phonon scattering in our device. Furthermore the average rate of energy loss per carrier e is proportional to ( e 2 − L 2 ), suggesting the heat diffusion rather than acoustic phonon processes in our system. The long energy relaxation times due to the weak electron-phonon coupling in CVD graphene capped with h-BN layer as well as in exfoliated multilayer graphene can find applications in hot carrier graphene-based devices.

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Mesoscopic conductance fluctuations in multi-layer graphene

Cited by 12 publications

References 72 publications

Impact of nitrogen doping on the band structure and the charge carrier scattering in monolayer graphene

Impact of nitrogen doping on the band structure and the charge carrier scattering in monolayer graphene

High Current-Induced Electron Redistribution in a CVD-Grown Graphene Wide Constriction

Hot Carriers in CVD-Grown Graphene Device with a Top h-BN Layer

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