Spatial-Temporal Imaging of Anisotropic Photocarrier Dynamics in Black Phosphorus

Abstract

As an emerging single elemental layered material with a low symmetry in-plane crystal lattice, black phosphorus (BP) has attracted significant research interest owing to its unique electronic and optoelectronic properties, including its widely tunable bandgap, polarization dependent photoresponse and highly anisotropic in-plane charge transport. Despite extensive study of the steady-state charge transport in BP, there has not been direct characterization and visualization of the hot carriers dynamics in BP immediately after photoexcitation, which is crucial to understanding the performance of BP-based optoelectronic devices. Here we use the newly developed scanning ultrafast electron microscopy (SUEM) to directly visualize the motion of photo-excited hot carriers on the surface of BP in both space and time. We observe highly anisotropic in-plane diffusion of hot holes, with a 15-times higher diffusivity along the armchair (x-) direction than that along the zigzag (y-) direction. Our results provide direct evidence of anisotropic hot carrier transport in BP and demonstrate the capability of SUEM to resolve ultrafast hot carrier dynamics in layered two-dimensional materials.

arXiv comment21 pages, 6 figures

References in corpus (24)

• Black phosphorus field-effect transistors
• Phosphorene: A New 2D Material with High Carrier Mobility
• High-mobility transport anisotropy and linear dichroism in few-layer black phosphorus
• Rediscovering Black Phosphorus: A Unique Anisotropic 2D Material for Optoelectronics and Electronics
• Tunable Band Gap and Anisotropic Optical Response in Few-layer Black Phosphorus
• Isolation and characterization of few-layer black phosphorus
• Strain-induced gap modification in black phosphorus
• The Renaissance of Black Phosphorus
• Broadband Linear-Dichroic Photodetector in a Black Phosphorus Vertical p-n Junction
• Electric field effect in ultrathin black phosphorus
• Observation of tunable bandgap and anisotropic Dirac semimetal state in black phosphorus
• Waveguide-integrated black phosphorus photodetector with high responsivity and low dark current
• Direct Observation of Layer-Dependent Electronic Structure in Phosphorene
• Black Phosphorus Mid-Infrared Photodetectors with High Gain
• Enhanced Thermoelectric Efficiency via Orthogonal Electrical and Thermal Conductances in Phosphorene
• High quality sandwiched black phosphorus heterostructure and its quantum oscillations
• Quantum Hall Effect in Black Phosphorus Two-dimensional Electron Gas
• Efficient Electrical Control of Thin-Film Black Phosphorus Bandgap
• Black Phosphorus Radio-Frequency Transistors
• Ab initio study of electron-phonon interaction in phosphorene
• Dynamical Evolution of Anisotropic Response in Black Phosphorus under Ultrafast Photoexcitation
• Revealing the Anisotropic Thermal Conductivity of Black Phosphorus using the Time-Resolved Magneto-Optical Kerr Effect
• Carrier Dynamics and Transient Photobleaching in Thin Layers of Black Phosphorus
• Dynamics of Photo-excited Hot Carriers in Hydrogenated Amorphous Silicon Imaged by 4D Electron Microscopy

Cited by in corpus (13)

• Mid-infrared polarized emission from black phosphorus light-emitting diodes
• The Optical Properties and Plasmonics of Anisotropic 2-Dimensional Materials
• Accessing the anisotropic non-thermal phonon populations in black phosphorus
• Scanning Ultrafast Electron Microscopy: A Novel Technique to Probe Photocarrier Dynamics with High Spatial and Temporal Resolutions
• Anisotropic Nonequilibrium Lattice Dynamics of Black Phosphorus
• Anisotropic Charge Carrier and Coherent Acoustic Phonon Dynamics of Black Phosphorus Studied by Transient Absorption Microscopy
• Spatiotemporal Imaging of Thickness-Induced Band Bending Junctions
• Impact of photoexcitation on secondary electron emission: a Monte Carlo study
• Cross-Examination of Photoinitiated Carrier and Structural Dynamics of Black Phosphorus at Elevated Fluences
• Spectral responsivity and photoconductive gain in thin film black phosphorus photodetectors
• Carrier Density Oscillation in photoexcited Semiconductors
• Transient strain induced electronic structure modulation in a semiconducting polymer imaged by scanning ultrafast electron microscopy
• Electrical Control of Linear Dichroism in Black Phosphorus from the Visible to Mid-Infrared