Ultrafast Photoluminescence from Graphene

Abstract

Since graphene has no band gap, photoluminescence is not expected from relaxed charge carriers. We have, however, observed significant light emission from graphene under excitation by ultrashort (30-fs) laser pulses. Light emission was found to occur across the visible spectral range (1.7 - 3.5 eV), with emitted photon energies exceeding that of the excitation laser (1.5 eV). The emission exhibits a nonlinear dependence on the laser fluence. In two-pulse correlation measurements of the time-domain response, a dominant relaxation time of tens of femtoseconds is observed. A two-temperature model describing the electrons and their interaction with strongly coupled optical phonons can account for the experimental observations.

13 pages, 7 figures, supplemental material included

References in corpus (6)

• Universal Dynamic Conductivity and Quantized Visible Opacity of Suspended Graphene
• Intrinsic and Extrinsic Performance Limits of Graphene Devices on SiO2
• Measurement of the Optical Conductivity of Graphene
• Inelastic carrier lifetime in graphene
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Cited by in corpus (6)

• Intrinsic response time of graphene photodetectors
• Cooling of photoexcited carriers in graphene by internal and substrate phonons
• Photo-excited Carrier Dynamics and Impact Excitation Cascade in Graphene
• Observation of suppressed terahertz absorption in photoexcited graphene
• Nitrogen-Functionalized Graphene Nanoflakes (GNFs:N): Tunable Photoluminescence and Electronic Structures
• Evidence for Extraction of Photoexcited Hot Carriers from Graphene