Growth and structure of singly oriented single-layer tungsten disulfide on Au(111)

Abstract

We present a complete characterization at the nanoscale of the growth and structure of singlelayer tungsten disulfide (WS 2 ) epitaxially grown on Au(111). Following the growth process in real time with fast x-ray photoelectron spectroscopy, we obtain a singly-oriented layer by choosing the proper W evaporation rate and substrate temperature during the growth. Information about the morphology, size and layer stacking of the WS 2 layer were achieved by employing x-ray photoelectron diffraction and low-energy electron microscopy. The strong spin splitting in the valence band of WS 2 coupled with the single-orientation character of the layer make this material the ideal candidate for the exploitation of the spin and valley degrees of freedom.

The Transition From MoS2 Single-Layer to Bilayer Growth on the Au(111) Surface

“…The 3-fold symmetric pattern is typical for single-domain MoS 2 on Au(111) [25]. Furthermore, this 3-fold symmetry allows mirror domains of single-layer MoS 2 on Au(111) to be identified in dark-field (DF) LEEM by their integer beam intensity [15], similarly to the case of WS 2 on Au(111) [16]. Accordingly, their spatial distribution can be visualized by DF-LEEM performed at distinct electron energies (here, 31 and 41 eV) as demonstrated in Figures 2C,D.…”

“…Employing the specular (00) beam allows for bright-field imaging, while any other diffracted beam enables a so-called dark-field measurement. Dark-field imaging reveals the sample area contributing to the selected beam, which in our present case allows to differentiate between the two existing mirror domains of MoS 2 on Au(111) [15,16].…”

Electron–phonon coupling in single-layer MoS2

“…High quality SL TMDCs can be grown on different substrates instead of isolation by micro-mechanical exfoliation. It has recently become possible to grow large area [10,11], single orientation epitaxial SL MoS 2 [12] and WS 2 [13] on Au(111). The very high quality of these samples offers the opportunity to study the spin texture [14] and electron-phonon coupling strength [15] near the valence band (VB) maximum at the K and K points experimentally and thus allowing access to parameters relevant for transport in hole-doped devices [16] or low-dimensional superconductivity [17].…”

Unusual reversibility in molecular break-up of PAHs: the case of pentacene dehydrogenation on Ir(111)

“…In order to shed light on the chemical identity of the C atoms producing the two different components we have performed X-ray photoelectron diffraction (XPD) simulations. XPD is a technique that has proven very effective to determine the adsorption site of molecules on surfaces, 40 to reveal the chemical identity of spectral features in core-level spectra, 41 to unravel the atomic and structural configuration of 2D materials on metallic single-crystal surfaces 42–44 and to investigate about the presence of corrugation or rotational crystalline domains in graphene, 45,46 . In this study we have divided the C atom population of a pentacene molecule into two families, those forming a bond with hydrogen and those at the centre of the molecules which are only C–C bonded.…”