Exfoliating pristine black phosphorus down to the monolayer: photo-oxidation and electronic confinement effects

Abstract

Thin layers of black phosphorus have recently raised interest for their two-dimensional (2D) semiconducting properties, such as tunable direct bandgap and high carrier mobilities. This lamellar crystal of P atoms stacked together by weak van der Waals forces can be exfoliated down to the stratophosphane monolayer (also called phosphorene) using procedures similar to those used for graphene. Properties of this 2D material are however challenging to probe due to a fast and ubiquitous degradation upon exposure to ambient conditions. Herein, we investigate the crystal degradation using in-situ Raman and transmission electron spectroscopies and highlight a process involving a photo-induced oxidation reaction with adsorbed oxygen in water. The experimental conditions to prepare and preserve mono-, bi- and multilayers of stratophosphane in their pristine states were determined. Study on these 2D layers provides new insights on the effect of confinement on the chemical reactivity and the vibrational modes of black phosphorus.

main text: 16 pages, 5 figures

References in corpus (1)

• Extraordinary Photoluminescence and Strong Temperature/Angle-Dependent Raman Responses in Few-Layer Phosphorene

Cited by in corpus (7)

• The Renaissance of Black Phosphorus
• Electrical characterization of fully encapsulated ultra thin black phosphorus-based heterostructures with graphene contacts
• Toward Air-Stable Multilayer Phosphorene Thin-Films and Transistors
• Gate Tunable Quantum Oscillations in Air-Stable and High Mobility Few-Layer Phosphorene Heterostructures
• Black phosphorus as a new broadband saturable absorber for infrared passively Q-switched fiber lasers
• Unambiguous identification of monolayer phosphorene by phase-shifting interferometry
• Black Phosphorus p-MOSFETs with High Transconductance and Nearly Ideal Subthreshold Slope