Ultrafast Dynamics of the Surface Photovoltage in Potassium Doped Black Phosphorus

Abstract

Black phosphorus is a quasi-two-dimensional layered semiconductor with a narrow direct band gap of 0.3 eV. A giant surface Stark effect can be produced by the potassium doping of black phosphorus, leading to a semiconductor to semimetal phase transition originating from the creation of a strong surface dipole and associated band bending. By using time- and angle-resolved photoemission spectroscopy, we report the partial photoinduced screening of this band bending by the creation of a compensating surface photovoltage. We further resolve the detailed dynamics of this effect at the pertinent timescales and the related evolution of the band structure near the Fermi level. We demonstrate that after a fast rise time, the surface photovoltage exhibits a plateau over a few tens of picoseconds before decaying on the nanosecond timescale. We support our experimental results with simulations based on drift-diffusion equations.

18 pages, 12 figures

References in corpus (12)

• 2D materials and van der Waals heterostructures
• The Renaissance of Black Phosphorus
• Ultrafast Optical Excitation of a Persistent Surface-State Population in the Topological Insulator Bi2Se3
• Tuning Electronic and Magnetic Properties of Early Transition Metal Dichalcogenides via Tensile Strain
• Universal Mechanism of Band-Gap Engineering in Transition-Metal Dichalcogenides
• Ultrafast Angle-Resolved Photoemission Spectroscopy of Quantum Materials
• Epitaxial Growth of Two-dimensional Insulator Monolayer Honeycomb BeO
• Plumbene on a magnetic substrate: a combined STM and DFT study
• Non-equilibrium Band Broadening, Gap Renormalization and Band Inversion in Black Phosphorus
• Microscopic mechanism of tunable band gap in potassium doped few-layer black phosphorus
• Electronic band structure of ultimately thin silicon oxide on Ru(0001)
• Dispersing and semi-flat bands in the wide band gap two-dimensional semiconductor bilayer silicon oxide

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