Spatially Resolved Electronic Properties of Single-Layer WS${}_2$ on Transition Metal Oxides

Abstract

There is a substantial interest in the heterostructures of semiconducting transition metal dichalcogenides (TMDCs) amongst each other or with arbitrary materials, through which the control of the chemical, structural, electronic, spintronic, and optical properties can lead to a change in device paradigms. A critical need is to understand the interface between TMDCs and insulating substrates, for example high-$\kappa$ dielectrics, which can strongly impact the electronic properties such as the optical gap. Here we show that the chemical and electronic properties of the single-layer (SL) TMDC, WS${}_2$, can be transferred onto high-$\kappa$ transition metal oxide substrates TiO${}_2$ and SrTiO${}_3$. The resulting samples are much more suitable for measuring their electronic and chemical structures with angle-resolved photoemission than their native-grown SiO${}_2$ substrates. We probe the WS${}_2$ on the micron scale across 100-micron flakes, and find that the occupied electronic structure is exactly as predicted for freestanding SL WS${}_2$ with a strong spin-orbit splitting of 420~meV and a direct band gap at the valence band maximum. Our results suggest that TMDCs can be combined with arbitrary multi-functional oxides, which may introduce alternative means of controlling the optoelectronic properties of such materials.

28 pages, 5 figures

References in corpus (12)

• Two Dimensional Atomic Crystals
• Ultrafast Charge Transfer in Atomically Thin MoS2/WS2 Heterostructures
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Mixed-Dimensional van der Waals Heterostructures
• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Probing Excitonic Dark States in Single-layer Tungsten Disulfide
• Quasiparticle band structures and optical properties of strained monolayer MoS2 and WS2
• Two dimensional semiconductors with possible high room temperature mobility
• Electrical Transport Properties of Single-Layer WS2
• Fast pick up technique for high quality heterostructures of bilayer graphene and hexagonal boron nitride
• Electronic Structure of Epitaxial Single-Layer MoS${}_2$
• Angle-resolved X-ray photoemission electron microscopy

Cited by in corpus (3)

• Understanding Variations in Circularly Polarized Photoluminescence in Monolayer Transition Metal Dichalcogenides
• Contact-Induced Semiconductor-to-Metal Transition in Single-Layer WS${}_2$
• Laser-patterned submicron Bi2Se3-WS2 pixels with tunable circular polarization at room temperature