Inter-Layer Screening Length to Electric Field in Thin Graphite Film

Miyazaki, Hisao; Odaka, S.; Sato, Takashi; Tanaka, Shiro; Goto, Hidenori; Kanda, Akinobu; Tsukagoshi, Kazuhito; Ootuka, Youiti; Aoyagi, Yoshinobu

doi:10.1143/apex.1.034007

Cited by 91 publications

(72 citation statements)

References 13 publications

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“…(4) The reatly reduced dielectric screening in the 2D graphene results in a very high Coulomb scattering rate 14,16 that is essential for establishing the transient, highly nonequilibrium carrier population, and the strong e-h recombination. In thicker graphene films, more effective screening, 17 and more attenuation of light could cause the PL to saturate.…”

Section: 12mentioning

confidence: 99%

Nonlinear broadband photoluminescence of graphene induced by femtosecond laser irradiation

et al. 2010

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Upon femtosecond laser irradiation, a bright, broadband photoluminescence is observed from graphene at frequencies well above the excitation frequency. Analyses show that it arises from radiative recombination of a broad distribution of nonequilibrium electrons and holes, generated by rapid scattering between photoexcited carriers within tens of femtoseconds after the optical excitation. Its highly unusual characteristics come from the unique electronic and structural properties of graphene.Graphene is an sp2-hybridized carbon monolayer that has many uncommon attributes, from exotic electrical 1 and thermal 2 transport to extraordinary mechanical properties. 3 It also exhibits unusual linear optical behavior, which shows a universal absorption constant 4 and can be effectively controlled by electrical gating. 5 The nonlinear optical response of graphene could be even more interesting: it is well known that unusual nonlinear optical phenomena can arise from low-dimensional confinement of carriers as has been demonstrated extensively in semiconductor quantum well structures. 6 Moreover, graphene has a unique band structure that could give rise to extraordinary nonlinear optical properties, yet such aspects have been overlooked so far.In this Rapid Communication, we report the observation of an unusually bright, broadband nonlinear photoluminescence (PL) generated in graphene upon femtosecond laser irradiation. It has a significant blueshifted component covering the entire visible spectrum when excited by near-infrared photons, and has very different characteristics from, for example, those of two-photon photoluminescence (TPPL) in noble metals. 7 Our analysis suggests that the graphene nonlinear PL arises from a broad distribution of nonequilibrium electron-hole (e-h) gas created via rapid scattering between a high density of photoexcited carriers. Although this mechanism is not limited to graphene, its two-dimensional (2D) nature and unusual band structure dramatically enhance the PL efficiency and bandwidth.Our experiments were performed with a 76 MHz Ti:Sapphire oscillator pumping an optical parametric oscillator with ~150 fs output pulses tunable within ~1.4-2.2 eV. As shown schematically in Fig. 1(a)_, the beam was focused on the sample at normal incidence, and the PL was collected in the backscattered direction. The signal was then detected by either a spectrograph equipped with a silicon charge-coupled device for monitoring spectra, or a single-photon counting silicon avalanche photodiode for detecting the integrated signal. The continuous-wave _cw_ Raman spectra were taken with a heliumblueshifted

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Section: 12mentioning

confidence: 99%

Nonlinear broadband photoluminescence of graphene induced by femtosecond laser irradiation

et al. 2010

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“…[20,21] For a multilayer system the effect of screening is important in determining the band structure, as it produces non-uniform charge densities across the layers. [14,15,[22][23][24][25][26][27][28] In this work, by using the self-consistent Hartree approximation we obtain potential energies of different layers for unbiased systems with three or more layers and biased systems with a perpendicular electric field for two or more layers. For unbiased graphene multilayers, peak values of the thermopower are close to each other irrespective of the model used.…”

Section: Introductionmentioning

confidence: 99%

Thermopower of multilayer graphene

Hao

Lee

2010

Phys. Rev. B

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We systematically calculate thermopower of biased and unbiased multilayer graphene systems. The effect of screening to a bias field perpendicular to the graphene planes is taken into account selfconsistently under the Hartree approximation. The model including nearest neighbor hopping and the more general Slonczewski-Weiss-McClure (SWMcC) model are both considered for a comparison. The effect of impurity scattering is studied for monolayer and unbiased bilayer graphene and is treated in terms of the self-consistent Born approximation. For a monolayer graphene, only when the effect of impurity scattering is taken into account, could all the qualitative aspects of the experimental results be correctly reproduced. Besides bilayer graphene, only trilayer graphene opens a small gap and shows a slight enhancement of thermopower under an external bias. The biased bilayer graphene shows the largest thermopower among all the systems studied.

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“…Graphene, an atomically thin two-dimensional (2D) allotrope of carbon, has been the subject of intensive research owing to its potential applications in electronic devices, 1,2 flexible and transparent electrodes, 3,4 ultrathin membranes, 5,6 sensors, 7 electromagnetic interference (EMI) shielding 8,9 and electromagnetic (EM) absorption materials, 10,11 and energy conversion and storage. 12,13 In general, the graphene is prepared on SiO 2 /Si substrate by means of mechanical exfoliation from bulk graphite, 14,15 chemical vapor deposition (CVD), 16,17 and negative carbon ion implantation.…”

Section: Introductionmentioning

confidence: 99%

“…v) From a thickness-dependent conductance of graphene films, the interlayer screening length for the external electric field has been determined to be 0.14 1.2 nm. 8,9,36 Hong et al have obtained the EMI shielding effectiveness (SE) of monolayer CVD graphene as 2.27 dB, which is seven times greater than gold film and can block ∼40% shielding of incident waves in frequency range of 2.2∼7.0 GHz. 37 Those screening lengths of 0.14 − 1.2 nm correspond to the thicknesses of 3∼4 atomic layers of carbon.…”

Section: Introductionmentioning

confidence: 99%

Coupling behaviors of graphene/SiO2/Si structure with external electric field

2017

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A traveling electric field in surface acoustic wave was introduced into the graphene/SiO2/Si sample in the temperature range of 15 K to 300 K. The coupling behaviors between the sample and the electric field were analyzed using two parameters, the intensity attenuation and time delay of the traveling-wave. The attenuation originates from Joule heat of the moving carriers, and the delay of the traveling-wave was due to electrical resistances of the fixed charge and the moving carriers with low mobility in the sample. The attenuation of the external electric field was observed in both Si crystal and graphene films in the temperature range. A large attenuation around 190 K, which depends on the strength of external electric field, was confirmed for the Si crystal. But, no significant temperature and field dependences of the attenuation in the graphene films were detected. On the other hand, the delay of the traveling-wave due to ionic scattering at low temperature side was observed in the Si crystal, but cannot be detected in the films of the mono-, bi- and penta-layer graphene with high conductivities. Also, it was indicated in this study that skin depth of the graphene film was less than thickness of two graphene atomic layers in the temperature range.

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Inter-Layer Screening Length to Electric Field in Thin Graphite Film

Cited by 91 publications

References 13 publications

Nonlinear broadband photoluminescence of graphene induced by femtosecond laser irradiation

Nonlinear broadband photoluminescence of graphene induced by femtosecond laser irradiation

Thermopower of multilayer graphene

Coupling behaviors of graphene/SiO2/Si structure with external electric field

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