Related papers: Photocarrier thermalization bottleneck in graphene
In this work, we report on hot carrier diffusion in graphene across large enough length scales that the carriers are not thermalized across the crystal. The carriers are injected into graphene at one site and their thermal transport is…
Dirac Fermion, which is the low energy collective excitation near the Dirac cone in monolayer graphene, have gained great attention by low energy Terahertz probe. In the case of undoped graphene, it has been generally understood that the…
The temporal dynamics of charge carriers determines the speed with which electronics can be realized in condensed matter, and their direct manipulation with optical fields promises electronic processing at unprecedented petahertz…
We report on resonance Raman spectroscopy measurements with excitation photon energy down to 1.16 eV on graphene, to study how low-energy carriers interact with lattice vibrations. Thanks to the excitation energy close to the Dirac point at…
Using the Boltzmann transport equation (BTE), we study the evolution of nonequilibrium carrier distributions in simple ($sp$) metals, assumed to have been instantaneously excited by an ultrafast laser pulse with photon energy $h \nu$. The…
This article reviews recent research for development of sensitive graphene photon detectors in the infrared/far infrared/THz range. For this range, graphene has promising potential in thermal photon detectors. Graphene has ultra-small…
The ultrafast dynamics of excited carriers in graphene is closely linked to the Dirac spectrum and plays a central role for many electronic and optoelectronic applications. Harvesting energy from excited electron-hole pairs, for instance,…
Using ultrafast optical pump-probe spectroscopy, we have measured carrier relaxation times in epitaxial graphene layers grown on SiC wafers. We find two distinct time scales associated with the relaxation of nonequilibrium photogenerated…
Near infrared pump-probe spectroscopy has been used to measure the ultrafast dynamics of photoexcited charge carriers in monolayer and multilayer graphene. We observe two decay processes occurring on 100 fs and 2 ps timescales. The first is…
We directly image hot spot formation in functioning mono- and bilayer graphene field effect transistors (GFETs) using infrared thermal microscopy. Correlating with an electrical-thermal transport model provides insight into carrier…
We predict that graphene is a unique system where disorder-assisted scattering (supercollisions) dominates electron-lattice cooling over a wide range of temperatures, up to room temperature. This is so because for momentum-conserving…
Gate-modulated low-temperature Raman spectra reveal that the electric field effect (EFE), pervasive in contemporary electronics, has marked impacts on long wavelength optical phonons of graphene. The EFE in this two dimensional honeycomb…
We examine the photoconductivity of an intrinsic graphene associated with far- and mid-infrared irradiation at low temperatures. The model under consideration accounts for the excitation of the electron-hole pairs by incident radiation, the…
Hot, dense phases of Dirac fermions - predicted to resemble relativistic plasma - are uniquely accessible through photoexcitation of pristine, charge neutral graphene. We demonstrate a sensitive temperature probe of the photoexcited Dirac…
The temperature dependence of electric transport properties of single-layer and few-layer graphene at large charge doping is of great interest both for the study of the scattering processes dominating the conductivity at different…
Direct and inverse Auger scattering are amongst the primary processes that mediate the thermalization of hot carriers in semiconductors. These two processes involve the annihilation or generation of an electron-hole pair by exchanging…
Ultrafast dynamics of graphite is investigated by time-resolved photoemission spectroscopy. We observe spectral features of direct photoexcitations, non-thermal electron distributions, and recovery dynamics occurring with two time scales…
Terahertz (THz) radiation has uses from security to medicine; however, sensitive room-temperature detection of THz is notoriously difficult. The hot-electron photothermoelectric effect in graphene is a promising detection mechanism:…
Photoexcitation of graphene leads to an interesting sequence of phenomena, some of which can be exploited in optoelectronic devices based on graphene. In particular, the efficient and ultrafast generation of an electron distribution with an…
The electronic properties of graphene are unique and are attracting increased attention to this novel 2-dimensional system. Its photonic properties are not less impressive. For example, this single atomic layer absorbs through direct…