相关论文: Femtosecond Pump-Probe Studies of Reduced Graphene…
Graphene is emerging as a viable alternative to conventional optoelectronic, plasmonic, and nanophotonic materials. The interaction of light with carriers creates an out-of-equilibrium distribution, which relaxes on an ultrafast timescale…
We present systematic thermal conductivity measurements of suspended thin graphite ribbons, 234-527 nm thick, using a four-probe 3-omega method. Unlike recent reports of phonon hydrodynamics and exceptionally high thermal conductivity in…
Femtosecond spectroscopy is an important tool for tracking rapid photoinduced processes in a variety of materials. To spatially map the processes in a sample would substantially expand the capabilities of the method. This is, however,…
Graphene oxide (GO) is reduced by Joule heating using in-situ transmission electron microscopy (TEM). The approach allows the simultaneous study of GO conductivity by electrical measurements and of its composition and structural properties…
Room temperature Terahertz stimulated emission and population inversion in optically pumped graphene is reported. We experimentally observe fast relaxation and relatively slow recombination dynamics of photogenerated electrons/holes in an…
We employ dual-gated 30{\deg}-twisted bilayer graphene to demonstrate simultaneous ultra-high mobility and conductivity (up to 40 mS at room temperature), unattainable in a single-layer of graphene. We find quantitative agreement with a…
We utilized the momentum transfer(Q)-dependence of Quasi-Elastic Neutron Scattering (QENS) to reveal the dynamics of water and ethanol confined in Graphene Oxide (GO) powder or membranes at different temperatures and in different…
We report results from ultrafast two-color optical pump-probe spectroscopy on bulk $\beta$-Ga$_2$O$_3$. A two-photon absorption scheme is used to photoexcite carriers with the pump pulse and free-carrier absorption of the probe pulse is…
Direct measurements of photoexcited carrier dynamics in nickel are made using few-femtosecond extreme ultraviolet (XUV) transient absorption spectroscopy at the nickel M$_{2,3}$ edge. It is observed that the core-level absorption lineshape…
We demonstrate the atomic layer deposition of high-quality HfO2 film on graphene and report the magnitude of remote oxide phonon (ROP) scattering in dual-oxide graphene transistors. Top gates with 30 nm HfO2 oxide layer exhibit excellent…
We investigate the carrier mobility in mono- and bi-layer graphene with a top HfO2 dielectric, as a function of the HfO2 film thickness and temperature. The results show that the carrier mobility decreases during the deposition of the first…
In recent years, phonon electron carrier dragging has emerged as an innovative approach for modulating energy transfer in low dimensional systems. In this Letter, we explore the fundamental mechanisms of electron-phonon coupling and the…
We theoretically examine the effect of carrier-carrier scattering processes (electron-hole and electron-electron) on the intraband radiation absorption and their contribution to the net dynamic conductivity in optically or electrically…
We report evidence of nonequilibrium hot carriers extraction from graphene by gate-dependent photocurrent study. Scanning photocurrent excited by femtosecond pulse laser shows unusual gate dependence compared with continuous wave (CW) laser…
Oxygen molecules are found to exhibit non-negligible reactivity with graphene under strong light irradiation in the presence of water. The reaction is triggered by the laser Raman spectroscopy measurement itself, and the D band (ca. 1340…
We present a femtosecond time-resolved optical spectroscopy (TRS) as an experimental tool to probe the changes in the low energy electronic density of states as a result of short and long range charge density wave order. In these…
We demonstrate the excellent temperature sensing property of a chemically synthesized reduced graphene oxide (rGO). It is found that with increase in temperature from 80 to 375K, the resistivity of reduced graphene oxide monotonically…
The transient evolution of carriers in an intrinsic graphene under ultrafast excitation, which is caused by the collisionless interband transitions, is studied theoretically. The energy relaxation due to the quasielastic acoustic phonon…
Using ultrafast pump-probe reflectivity with 3.1 eV pump and coherent white light probe (1.1 to 2.6 eV), we show that graphene on gold nanostructures exhibits a strong coupling to the plasmonic resonances of the ordered lattice hole array,…
Molecular dynamics simulations are carried out to explore the dynamical crossover phenomenon in strongly confined and mildly supercooled water in graphene oxide nanopores. In contrast to studies where confinement is used to study the…