Tunable Ultrafast Thermal Relaxation in Graphene Measured by Continuous-Wave Photomixing
arXiv:1607.02181 · doi:10.1103/PhysRevLett.117.257401
Abstract
Hot electron effects in graphene are significant because of graphene's small electronic heat capacity and weak electron-phonon coupling, yet the dynamics and cooling mechanisms of hot electrons in graphene are not completely understood. We describe a novel photocurrent spectroscopy method that uses the mixing of continuous-wave lasers in a graphene photothermal detector to measure the frequency dependence and nonlinearity of hot-electron cooling in graphene as a function of the carrier concentration and temperature. The method offers unparalleled sensitivity to the nonlinearity, and probes the ultrafast cooling of hot carriers with an optical fluence that is orders of magnitude smaller than in conventional time-domain methods, allowing for accurate characterization of electron-phonon cooling near charge neutrality. Our measurements reveal that near the charge neutral-point the nonlinear power dependence of the electron cooling is dominated by disorder-assisted collisions, while at higher carrier concentrations conventional momentum-conserving cooling prevails in the nonlinear dependence. The relative contribution of these competing mechanisms can be electrostatically tuned through the application of a gate voltage -- an effect that is unique to graphene.
References in corpus (33)
- Boron nitride substrates for high-quality graphene electronics
- Electronic transport in two dimensional graphene
- Hot Carrier-Assisted Intrinsic Photoresponse in Graphene
- Thermoelectric and Magnetothermoelectric Transport Measurements of Graphene
- Photo-excitation Cascade and Multiple Carrier Generation in Graphene
- Sensitive Room-Temperature Terahertz Detection via Photothermoelectric Effect in Graphene
- Photo-Thermoelectric Effect at a Graphene Interface Junction
- Photocurrent imaging and efficient photon detection in a graphene transistor
- Ultrafast Photoluminescence from Graphene
- Hot Carrier Transport and Photocurrent Response in Graphene
- The role of contacts in graphene transistors: A scanning photocurrent study
- Photocurrent measurements of supercollision cooling in graphene
- Disorder-Assisted Electron-Phonon Scattering and Cooling Pathways in Graphene
- Carrier dynamics in epitaxial graphene close to the Dirac point
- Electronic Cooling in Graphene
- Ultrafast Relaxation Dynamics of Hot Optical Phonons in Graphene
- Electron-phonon heat transfer in monolayer and bilayer graphene
- High-Responsivity Graphene-Boron Nitride Photodetector and Autocorrelator in a Silicon Photonic Integrated Circuit
- Supercollision cooling in undoped graphene
- Energy Relaxation of Hot Dirac Fermions in Graphene
- Theory of thermopower in 2D graphene
- Photo-thermoelectric and photoelectric contributions to light detection in metal-graphene-metal photodetectors
- High Thermoelectric Power Factor in Graphene/hBN Devices
- Hot electron cooling by acoustic phonons in graphene
- Cooling of photoexcited carriers in graphene by internal and substrate phonons
- Nonlinear screening of charges induced in graphene by metal contacts
- Terahertz Nonlinearity in Graphene Plasmons
- Hot-carrier photocurrent effects at graphene-metal interfaces
- Competing Channels for Hot Electron Cooling in Graphene
- Surface polar optical phonon interaction induced many-body effects and hot-electron relaxation in graphene
- Transient absorption and photocurrent microscopy show hot electron supercollisions describe the rate-limiting relaxation step in graphene
- Super-Planckian electron cooling in a van der Waals stack
- Electron-phonon cooling in large monolayer graphene devices
Cited by in corpus (7)
- Out-of-plane heat transfer in van der Waals stacks: electron-hyperbolic phonon coupling
- Hot carriers in graphene -- fundamentals and applications
- Ultra-fast calorimetric measurements of the electronic heat capacity of graphene
- Optical Control of Chiral Charge Pumping in a Topological Weyl Semimetal
- Interface defect-assisted phonon scattering of hot carriers in graphene
- Phonon-assisted carrier cooling in h-BN/graphene van der Waals heterostructures
- A liquid nitrogen cooled superconducting transition edge sensor with ultra-high responsivity and GHz operation speeds