Fabrication and Imaging of Monolayer Phosphorene with Preferred Edge Configurations via Graphene-Assisted Layer-by-Layer Thinning

Abstract

Phosphorene, a monolayer of black phosphorus (BP), is an elemental two-dimensional material with interesting physical properties, such as high charge carrier mobility and exotic anisotropic in-plane properties. To fundamentally understand these various physical properties, it is critically important to conduct an atomic-scale structural investigation of phosphorene, particularly regarding various defects and preferred edge configurations. However, it has been challenging to investigate mono- and few-layer phosphorene because of technical difficulties arising in the preparation of a high-quality sample and damages induced during the characterization process. Here, we successfully fabricate high-quality monolayer phosphorene using a controlled thinning process with transmission electron microscopy, and subsequently perform atomic-resolution imaging. Graphene protection suppresses the e-beam-induced damage to multi-layer BP and one-side graphene protection facilitates the layer-by-layer thinning of the samples, rendering high-quality monolayer and bilayer regions. We also observe the formation of atomic-scale crystalline edges predominantly aligned along the zigzag and (101) terminations, which is originated from edge kinetics under e-beam-induced sputtering process. Our study demonstrates a new method to image and precisely manipulate the thickness and edge configurations of air-sensitive two-dimensional materials.

21 pages, 5 figures

References in corpus (10)

• Effective Passivation of Exfoliated Black Phosphorus Transistors against Ambient Degradation
• The Renaissance of Black Phosphorus
• Strain-Engineering Anisotropic Electrical Conductance of Phosphorene and Few-Layer Black Phosphorus
• Environmental instability of few-layer black phosphorus
• Phase coexistence and metal-insulator transition in few-layer phosphorene: A computational study
• Oxygen defects in phosphorene
• In Situ Thermal Decomposition of Exfoliated Two-Dimensional Black Phosphorus
• Edge effects on the electronic properties of phosphorene nanoribbons
• Atomic-scale imaging of few-layer black phosphorus and its reconstructed edge
• Strain-controlled fundamental gap and structure of bulk black phosphorus

Cited by in corpus (1)

• Edge and sublayer degrees of freedom for phosphorene nanoribbons with twofold-degenerate edge bands via electric field