The ultrafast dynamics and conductivity of photoexcited graphene at different Fermi energies

Tomadin, Andrea; Hornett, Samuel M.; Wang, Hai I.; Alexeev, Evgeny M.; Candini, Andrea; Coletti, Camilla; Turchinovich, Dmitry; Kläui, Mathias; Bonn, Mischa; Koppens, Frank H. L.; Hendry, Euan; Polini, Marco; Tielrooij, Klaas‐Jan

doi:10.1126/sciadv.aar5313

Cited by 116 publications

(151 citation statements)

References 84 publications

Supporting

Mentioning

147

Contrasting

Order By: Relevance

“…Recently, Tomadin et al [191] provided a comprehensive picture of ultrafast carrier dynamics and electronic relaxation after optical photoexcitation, see also Figure 9 for illustration. They employed optical pump-THz probe experiments in gated CVD-grown single layer graphene.…”

Section: Thz Properties Of Graphenementioning

confidence: 99%

See 1 more Smart Citation

Terahertz Spectroscopy of Nanomaterials: a Close Look at Charge‐Carrier Transport

Kužel

Němec

2019

Advanced Optical Materials

View full text Add to dashboard Cite

Transport of charges is a fundamental process in many high-tech applications including photovoltaic or optoelectronic devices, but also in more ordinary components such as unsophisticated wires and other circuitry. The development of nanotechnologies resulted in the fabrication of highly complex materials consisting of a large variety of nanosized elements, which inevitably involve a multitude of charge transport processes occurring on various time-and length-scales. Figure 1 summarizes the most common nanoelements with high application potential.For example, the electrodes employed in Grätzel solar cells [1] are composed of percolated networks of a huge number of metal oxide nanoparticles (top-left panel in Figure 1). Colloidal nanocrystals form the basis for thin film electronics and flexible electronic devices. [2] The synthetic approaches control their composition, size and electronic structure (energy levels, density of states within the bands and in the bandgap) and the charge-carrier transport. [2,3] Nanowires and nanotubes made of conventional semiconductors are quasi 1D systems combining Terahertz spectroscopy has been used for almost two decades for investigations of nanomaterials, including nanocrystals, nanoparticles, nanowires, nanotubes or 2D crystals. Its great importance stems from the fact that it is a noncontact method and, owing to its high frequency and broadband character, it is capable of characterizing charge transport properties within individual nano-objects but also among them. In addition, probing of photoinitiated ultrafast charge dynamics is possible thanks to the sub-picosecond time resolution. Despite this unprecedented potential, the interpretation of the measured terahertz conductivity spectra in many materials is still intensively debated. Herein is presented a review of the experiments performed on nanostructures of conventional semiconductors and on carbon nanomaterials (graphene and carbon nanotubes) during the past decade. The state of the art of the theoretical formalism is provided and discussed, including the intrinsic response, as well as the role of inherent heterogeneity and of the experimental conditions.

show abstract

Section: Thz Properties Of Graphenementioning

confidence: 99%

“…Optical Mater. [191] Copyright 2018. Scheme of the Dirac cones for the a) weak doping with E F = 50 meV and b) strong doping with E F = 400 meV; the gray level indicates occupation of states in steady state.…”

Section: Thz Properties Of Graphenementioning

confidence: 99%

Terahertz Spectroscopy of Nanomaterials: a Close Look at Charge‐Carrier Transport

Kužel

Němec

2019

Advanced Optical Materials

View full text Add to dashboard Cite

show abstract

“…Indeed, its unique electronic bandstructure has led to proposed applications including photovoltaics, display panels, and sensors, and research is slowly beginning to move from the laboratory to industry 2,3 . Nurturing this move, terahertz (THz) spectroscopy has emerged as a tool wellsuited to characterize graphene carrier dynamics [4][5][6][7][8] .…”

Section: Introductionmentioning

confidence: 99%

Effect of microscopic scattering on the nonlinear transmission of terahertz fields through monolayer graphene

Helt

Dignam

2019

Phys. Rev. B

View full text Add to dashboard Cite

We consider the nonlinear terahertz response of n-doped monolayer graphene at room temperature using a microscopic theory of carrier dynamics. Our tight-binding model treats the carrier-field interaction in the length gauge, includes phonon as well as short-range neutral-impurity scattering, and fully accounts for the intrinsic nonlinear response of graphene near the Dirac point. Treating each interaction microscopically allows us to separate contributions from current clipping, phonon creation, and elastic impurity scattering. Although neutral impurity scattering and phonon scattering are both highly energy-dependent, we find that they impact conduction-band electron dynamics very differently, and that together they can help explain experimental results concerning field-dependent terahertz transmission through graphene. arXiv:1811.02730v1 [cond-mat.mes-hall]

show abstract

“…Interestingly, along with the subpicosecond transient response ruled by the many-body Coulomb inter-actions, a similar long-lived decay process around the VHs was observed as well in pump-probe optical absorption spectroscopy of graphite [21]. However, when it comes to the theoretical considerations, most of them are dealing with the low-energy (THz) transient optical response [36][37][38][39] or they are parameter-based [22,34], while the only available ab initio studies of phonon-assisted optical absorption in high-energy regime of graphene are for equilibrium condition [8,35]. Even more, recent study of phonon impact on optical absorption is conflicting with experiments, showing only an increase of absorption around the VHs and no band renormalization due to EPC [35].…”

Section: Introductionmentioning

confidence: 64%

Phonon-assisted processes in the ultraviolet-transient optical response of graphene

Novko

Kralj

2019

npj 2D Mater Appl

View full text Add to dashboard Cite

Many recent experiments investigated potential and attractive means of modifying many-body interactions in two-dimensional materials through time-resolved spectroscopy techniques. However, the role of ultrafast phonon-assisted processes in two-dimensional systems is rarely discussed in depth. Here, we investigate the role of electron-phonon interaction in the transient optical absorption of graphene by means of first-principles methods. It is shown at equilibrium that the phonon-assisted transitions renormalize significantly the electronic structure. As a result, absorption peak around the Van Hove singularity broadens and redshifts by around 100 meV. In addition, temperature increase and chemical doping are shown to notably enhance these phonon-assisted features. In the photoinduced transient response we obtain spectral changes in close agreement with the experiments, and we associate them to the strong renormalization of occupied and unoccupied π bands, which predominantly comes from the coupling with the zone-center E2g optical phonon. Our estimation of the Coulomb interaction effects shows that the phonon-assisted processes can have a dominant role even in the subpicosecond regime. arXiv:1911.04826v1 [cond-mat.mtrl-sci]

show abstract

The ultrafast dynamics and conductivity of photoexcited graphene at different Fermi energies

Abstract: The ultrafast dynamics and conductivity of photoexcited graphene can be explained using solely electronic effects.

Cited by 116 publications

References 84 publications

Terahertz Spectroscopy of Nanomaterials: a Close Look at Charge‐Carrier Transport

Terahertz Spectroscopy of Nanomaterials: a Close Look at Charge‐Carrier Transport

Effect of microscopic scattering on the nonlinear transmission of terahertz fields through monolayer graphene

Phonon-assisted processes in the ultraviolet-transient optical response of graphene

Contact Info

Product

Resources

About