Unraveling the Band Structure and Orbital Character of a π-Conjugated 2D Graphdiyne-Based Organometallic Network.

Graphdiyne-based carbon systems generate intriguing layered sp-sp organometallic lattices, characterized by flexible acetylenic groups connecting planar carbon units through metal centers. At their thinnest limit, they can result in 2D organometallic networks exhibiting unique quantum properties and even confining the surface states of the substrate, which is of great importance for fundamental studies. In this work, the on-surface synthesis of a highly crystalline 2D organometallic network grown on Ag(111) is presented.

Interface coupling in Au-supported MoS-WS heterobilayers grown by pulsed laser deposition.

Van der Waals heterostructures of transition metal dichalcogenides (TMDs) are promising systems for engineering functional layered 2D materials with tailored properties. In this work, we study the growth of WS/MoS and MoS/WS heterobilayers by pulsed laser deposition (PLD) under ultra-high vacuum conditions. Using Au(111) as growth substrate, we investigated the heterobilayer morphology and structure at the nanoscale by scanning tunneling microscopy.

Steric hindrance in the on-surface synthesis of diethynyl-linked anthracene polymers.

Hybrid sp-sp structures can be efficiently obtained on metal substrates on-surface synthesis. The choice of both the precursor and the substrate impacts on the effectiveness of the process and the stability of the formed structures. Here we demonstrate that using anthracene-based precursor molecules on Au(111) the formation of polymers hosting sp carbon chains is affected by the steric hindrance between aromatic groups.

Interface-Driven Assembly of Pentacene/MoS Lateral Heterostructures.

Mixed-dimensional van der Waals heterostructures formed by molecular assemblies and 2D materials provide a novel platform for fundamental nanoscience and future nanoelectronics applications. Here we investigate a prototypical hybrid heterostructure between pentacene molecules and 2D MoS nanocrystals, deposited on Au(111) by combining pulsed laser deposition and organic molecular beam epitaxy. The obtained structures were investigated in situ by scanning tunneling microscopy and spectroscopy and analyzed theoretically by density functional theory calculations.

Hydrophilic Character of Single-Layer MoS Grown on Ag(111).

The study of MoS/metal interfaces is crucial for engineering efficient semiconductor-metal contacts in 2D MoS-based devices. Here we investigate a MoS/Ag heterostructure fabricated by growing a single MoS layer on Ag(111) by pulsed laser deposition under ultrahigh vacuum (UHV) conditions. The surface structure is observed in situ by scanning tunneling microscopy, revealing the hexagonal moiré pattern characteristic of the clean MoS/Ag(111) interface.

Scanning tunneling microscopy and Raman spectroscopy of polymeric sp-sp carbon atomic wires synthesized on the Au(111) surface.

Long linear carbon nanostructures based on sp-hybridization can be synthesized by exploiting on-surface synthesis of halogenated precursors evaporated on Au(111), thus opening a way to investigations by surface-science techniques. By means of an experimental approach combining scanning tunneling microscopy and spectroscopy (STM and STS) with ex situ Raman spectroscopy we investigate the structural, electronic and vibrational properties of polymeric sp-sp2 carbon atomic wires composed by sp-carbon chains connected through phenyl groups. Density-functional-theory (DFT) calculations of the structure and the electronic density of states allow us to simulate STM images and to compute Raman spectra.

Pulsed laser deposition of single-layer MoS on Au(111): from nanosized crystals to large-area films.

Molybdenum disulphide (MoS) is a promising material for heterogeneous catalysis and novel two-dimensional (2D) optoelectronic devices. In this work, we synthesized single-layer (SL) MoS structures on Au(111) by pulsed laser deposition (PLD) under ultra-high vacuum (UHV) conditions. By controlling the PLD process, we were able to tune the sample morphology from low-coverage SL nanocrystals to large-area SL films uniformly wetting the whole substrate surface.

Pulsed laser deposition of two-dimensional ZnO nanocrystals on Au(111): growth, surface structure and electronic properties.

Two-dimensional (2D) ZnO structures have been deposited on the Au(111) surface by means of the pulsed laser deposition technique. In situ scanning tunneling microscopy and scanning tunneling spectroscopy measurements have been performed to characterize morphological, structural and electronic properties of 2D ZnO at the nanoscale. Starting from a sub-monolayer coverage, we investigated the growth of ZnO, identifying different atomic layers (up to the fifth).

Note: Fabrication and characterization of molybdenum tips for scanning tunneling microscopy and spectroscopy.

We present a method for the preparation of bulk molybdenum tips for Scanning Tunneling Microscopy and Spectroscopy and we assess their potential in performing high resolution imaging and local spectroscopy by measurements on different single crystal surfaces in UHV, namely, Au(111), Si(111)-7 × 7, and titanium oxide 2D ordered nanostructures supported on Au(111). The fabrication method is versatile and can be extended to other metals, e.g.