Efficacy of Boron Nitride Encapsulation against Plasma-Processing in van der Waals Heterostructures

Abstract

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) are the subject of intense investigation for applications in optics, electronics, catalysis, and energy storage. Their optical and electronic properties can be significantly enhanced when encapsulated in an environment that is free of charge disorder. Because hexagonal boron nitride (h-BN) is atomically thin, highly-crystalline, and is a strong insulator, it is one of the most commonly used 2D materials to encapsulate and passivate TMDCs. In this report, we examine how ultrathin h-BN shields an underlying MoS2 TMDC layer from the energetic argon plasmas that are routinely used during semiconductor device fabrication and post-processing. Aberration-corrected Scanning Transmission Electron Microscopy is used to analyze defect formation in both the h-BN and MoS2 layers, and these observations are correlated with Raman and photoluminescence spectroscopy. Our results highlight that h-BN is an effective barrier for short plasma exposures (< 30 secs) but is ineffective for longer exposures, which result in extensive knock-on damage and amorphization in the underlying MoS2.

References in corpus (13)

• scikit-image: Image processing in Python
• Emerging Device Applications for Semiconducting Two-Dimensional Transition Metal Dichalcogenides
• Micrometer-scale ballistic transport in encapsulated graphene at room temperature
• Mixed-Dimensional van der Waals Heterostructures
• Exciton physics and device application of two-dimensional transition metal dichalcogenide semiconductors
• High Mobility Ambipolar MoS2 Field-Effect Transistors: Substrate and Dielectric Effects
• The hot pick-up technique for batch assembly of van der Waals heterostructures
• Plasma-assisted fabrication of monolayer phosphorene and its Raman characterization
• High quality sandwiched black phosphorus heterostructure and its quantum oscillations
• Spontaneous doping of the basal plane of MoS2 single-layers through oxygen substitution under ambient conditions
• Robust fractional quantum Hall states and continuous quantum phase transitions in a half-filled bilayer graphene Landau level
• Electrical property tuning via defect engineering of single layer MoS2 by oxygen plasma
• Optimization of graphene dry etching conditions via combined microscopic and spectroscopic analysis