Doping Dependence of the Raman Spectrum of Defected Graphene

Bruna, Matteo; Ott, A. K.; Ijäs, Mari; Yoon, Duhee; Sassi, Ugo; Ferrari, Andrea C.

doi:10.1021/nn502676g

Cited by 331 publications

(343 citation statements)

References 48 publications

Supporting

Mentioning

316

Contrasting

Order By: Relevance

“…2 compares the Raman spectra of the as-prepared SLG on Si/SiO 2 and after transfer on GaAs. The analysis of G peak position, Pos(G), its full width at half maximum, FWHM(G), Pos(2D) and the area and intensity ratios of 2D and G peaks allow us to monitor the amount and type of doping 33,35,37,38 . This indicates a small pdoping for the as-prepared sample, decreasing to below 100 meV for the transferred sample 33,35,37 .…”

Section: Resultsmentioning

confidence: 99%

Anomalous low-temperature Coulomb drag in graphene-GaAs heterostructures

et al. 2014

View full text Add to dashboard Cite

Vertical heterostructures combining different layered materials offer novel opportunities for applications and fundamental studies. Here we report a new class of heterostructures comprising a single-layer (or bilayer) graphene in close proximity to a quantum well created in GaAs and supporting a high-mobility two-dimensional electron gas. In our devices, graphene is naturally hole-doped, thereby allowing for the investigation of electron-hole interactions. We focus on the Coulomb drag transport measurements, which are sensitive to many-body effects, and find that the Coulomb drag resistivity significantly increases for temperatures o5-10 K. The low-temperature data follow a logarithmic law, therefore displaying a notable departure from the ordinary quadratic temperature dependence expected in a weakly correlated Fermi-liquid. This anomalous behaviour is consistent with the onset of strong interlayer correlations. Our heterostructures represent a new platform for the creation of coherent circuits and topologically protected quantum bits.

show abstract

Section: Resultsmentioning

confidence: 99%

Anomalous low-temperature Coulomb drag in graphene-GaAs heterostructures

et al. 2014

View full text Add to dashboard Cite

show abstract

“…52,53 In such studies, an accurate determination of E F (hence of the gate capacitance) as a function of the gate voltage is a critical requirement. However, as opposed to solid state FETs, in which the oxide dielectric constant and thickness can be known with accuracy, the thickness of the electrical double layer may be highly arXiv:1502.06849v2 [cond-mat.mes-hall] 16 Apr 2015 sensitive to the device geometry, fluctuate spatially and vary over time. This further highlights the need for (i) robust methods for device fabrication and, (ii) accurate tools to experimentally measure the gate capacitance.…”

Section: Introductionmentioning

confidence: 99%

Raman spectroscopy of electrochemically gated graphene transistors: Geometrical capacitance, electron-phonon, electron-electron, and electron-defect scattering

2015

View full text Add to dashboard Cite

We report a comprehensive micro-Raman scattering study of electrochemically-gated graphene field-effect transistors. The geometrical capacitance of the electrochemical top-gates is accurately determined from dual-gated Raman measurements, allowing a quantitative analysis of the frequency, linewidth and integrated intensity of the main Raman features of graphene. The anomalous behavior observed for the G-mode phonon is in very good agreement with theoretical predictions and provides a measurement of the electron-phonon coupling constant for zone-center (Γ point) optical phonons. In addition, the decrease of the integrated intensity of the 2D-mode feature with increasing doping, makes it possible to determine the electron-phonon coupling constant for near zone-edge (K and K' points) optical phonons. We find that the electron-phonon coupling strength at Γ is five times weaker than at K (K'), in very good agreement with a direct measurement of the ratio of the integrated intensities of the resonant intra-(2D') and inter-valley (2D) Raman features. We also show that electrochemical reactions, occurring at large gate biases, can be harnessed to efficiently create defects in graphene, with concentrations up to approximately 1.4 × 10 12 cm −2 . At such defect concentrations, we estimate that the electron-defect scattering rate remains much smaller than the electron-phonon scattering rate. The evolution of the G-and 2D-mode features upon doping remain unaffected by the presence of defects and the doping dependence of the D mode closely follows that of its two-phonon (2D mode) overtone. Finally, the linewidth and frequency of the G-mode phonon as well as the frequencies of the G-and 2D-mode phonons in doped graphene follow sample-independent correlations that can be utilized for accurate estimations of the charge carrier density.

show abstract

“…We also get I(D)/I(G)∼0.14, indicating that the fabrication process does introduce significant defects in the SLG electrode [57,60].…”

Section: Introductionmentioning

confidence: 70%

Vertically Illuminated, Resonant Cavity Enhanced, Graphene–Silicon Schottky Photodetectors

et al. 2017

Self Cite

View full text Add to dashboard Cite

We report vertically-illuminated, resonant cavity enhanced, graphene-Si Schottky photodetectors (PDs) operating at 1550nm. These exploit internal photoemission at the graphene-Si interface. To obtain spectral selectivity and enhance responsivity, the PDs are integrated with an optical cavity, resulting in multiple reflections at resonance, and enhanced absorption in graphene. Our devices have wavelength-dependent photoresponse with external (internal) responsivity∼20mA/W (0.25A/W). The spectral-selectivity may be further tuned by varying the cavity resonant wavelength. Our devices pave the way for developing high responsivity hybrid graphene-Si free-space illuminated PDs for free-space optical communications, coherence optical tomography and light-radars.

show abstract

Doping Dependence of the Raman Spectrum of Defected Graphene

Cited by 331 publications

References 48 publications

Anomalous low-temperature Coulomb drag in graphene-GaAs heterostructures

Anomalous low-temperature Coulomb drag in graphene-GaAs heterostructures

Raman spectroscopy of electrochemically gated graphene transistors: Geometrical capacitance, electron-phonon, electron-electron, and electron-defect scattering

Vertically Illuminated, Resonant Cavity Enhanced, Graphene–Silicon Schottky Photodetectors

Contact Info

Product

Resources

About