Subwavelength THz imaging of graphene photoconductivity

Abstract

Using a spatially structured, optical pump pulse with a THz probe pulse, we are able to determine spatial variations of the ultrafast THz photoconductivity with sub-wavelength resolution (75 $\mu m\approx \lambda /5$ at 0.8 THz) in a planar graphene sample. We compare our results to Raman spectroscopy and correlate the existence of the spatial inhomogeneities between the two measurements. We find a strong correlation with inhomogeneity in electron density. This demonstrates the importance of eliminating inhomogeneities in doping density during CVD growth and fabrication for photoconductive devices.

References in corpus (28)

• The electronic properties of graphene
• The Raman Fingerprint of Graphene
• Large-Area Synthesis of High-Quality and Uniform Graphene Films on Copper Foils
• Quantifying defects in graphene via Raman spectroscopy at different excitation energies
• Electrochemically Top Gated Graphene: Monitoring Dopants by Raman Scattering
• Probing the Nature of Defects in Graphene by Raman Spectroscopy
• Uniaxial Strain in Graphene by Raman Spectroscopy: G peak splitting, Gruneisen Parameters and Sample Orientation
• Control and Characterization of Individual Grains and Grain Boundaries in Graphene Grown by Chemical Vapor Deposition
• Optical Separation of Mechanical Strain from Charge Doping in Graphene
• Atmospheric Oxygen Binding and Hole Doping in Deformed Graphene on a SiO2 Substrate
• Origin of Spatial Charge Inhomogeneity in Graphene
• Measurement of Ultrafast Carrier Dynamics in Epitaxial Graphene
• Ultrafast Optical-Pump Terahertz-Probe Spectroscopy of the Carrier Relaxation and Recombination Dynamics in Epitaxial Graphene
• Photo-excitation Cascade and Multiple Carrier Generation in Graphene
• Non-adiabatic Kohn-anomaly in a doped graphene monolayer
• Non-invasive, near-field terahertz imaging of hidden objects using a single pixel detector
• Raman spectroscopy as probe of nanometer-scale strain variations in graphene
• Strain-dependent Splitting of Double Resonance Raman Scattering Band in Graphene
• Ultrafast Relaxation Dynamics of Hot Optical Phonons in Graphene
• Raman Spectroscopy of Electrochemically-Gated Graphene Transistors: Geometrical Capacitance, Electron-Phonon, Electron-Electron, and Electron-Defect Scattering
• Semiconducting-to-metallic photoconductivity crossover and temperature-dependent Drude weight in graphene
• Extreme sensitivity of graphene photoconductivity to environmental gases
• Quasi-Periodic Nanoripples in Graphene Grown by Chemical Vapor Deposition and Its Impact on Charge Transport
• Competing Ultrafast Energy Relaxation Pathways in Photoexcited Graphene
• Tuning Optical Conductivity of Large-Scale CVD Graphene by Strain Engineering
• Hot phonon decay in supported and suspended exfoliated graphene
• Strain engineering on graphene towards tunable and reversible hydrogenation
• Nonequilibrium plasmons with gain in graphene

Cited by in corpus (4)

• Boosting the Terahertz Photoconductive Antenna Performance with Optimized Plasmonic Nanostructures
• Very-Large-Scale Reconfigurable Intelligent Surfaces for Dynamic Control of Terahertz and Millimetre Waves
• Multi-wavelength ghost imaging: a review
• Efficient Fourier single-pixel imaging with Gaussian random sampling