Two-probe study of hot carriers in reduced graphene oxide
arXiv:1103.0728 · doi:10.1063/1.3573674
Abstract
The energy relaxation of carriers in reduced graphene oxide thin films is studied using optical pump-probe spectroscopy with two probes of different colors. We measure the time difference between peaks of the carrier density at each probing energy by measuring a time-resolved differential transmission and find that the carrier density at the lower probing energy peaks later than that at the higher probing energy. Also, we find that the peak time for the lower probing energy shifts from about 92 to 37 fs after the higher probing energy peak as the carrier density is increased from 1.5E12 to 3E13 per square centimeter, while no noticeable shift is observed in that for the higher probing energy. Assuming the carriers rapidly thermalize after excitation, this indicates that the optical phonon emission time decreases from about 50 to about 20 fs and the energy relaxation rate increases from 4 to 10 meV/fs. The observed density dependence is inconsistent with the phonon bottleneck effect.
10 pages, 4 figures
References in corpus (12)
- Electric Field Effect in Atomically Thin Carbon Films
- Ultrafast Photoluminescence from Graphene
- Ultrafast Relaxation Dynamics of Hot Optical Phonons in Graphene
- Femtosecond carrier dynamics and saturable absorption in graphene suspensions
- Electron and optical phonon temperatures in electrically biased graphene
- Slowing hot carrier relaxation in graphene using a magnetic field
- Ballistic Hot Electron Transport in Graphene
- Hot carrier diffusion in graphene
- Phonon-induced many-body renormalization of graphene electronic properties
- Fluorescence of laser created electron-hole plasma in graphene
- Femtosecond Pump-Probe Studies of Reduced Graphene Oxide Thin Films
- Broadband electromagnetic response and ultrafast dynamics of few-layer epitaxial graphene