Growth and transport properties of thin Ag films on Si(111) are investigated by scanning tunneling microscopy and in situ resistivity measurements. At low coverage, the Ag adatoms form isolated islands with a strongly preferred height and flat tops, rather than commonly observed pyramids. Such plateaus increase their lateral extent with coverage without changing height, forming a percolated network with sharply reduced resistivity above a critical coverage. This behavior suggests how the quantized electrons confined in the Ag islands could influence the growth, and may provide a unique pathway to prepare nanometer-scale structures with intriguing mesoscopic properties.

The ongoing miniaturization of electronic devices has boosted the development of new post-silicon two-dimensional (2D) semiconductors, such as transition metal dichalcogenides, one of the most prominent materials being molybdenum disulfide (MoS₂). A major obstacle for the industrial production of MoS₂-based devices lies in the growth techniques. These must ensure the reliable fabrication of MoS₂ with tailored 2D properties to allow for the typical direct bandgap of 1.9 eV, while maintaining large-area growth and device compatibility. In this work, we used a versatile and industrially scalable MoS₂ growth method based on ionized jet deposition and annealing at 250 °C, through which a 3D stable and scalable material exhibiting excellent electronic and optical properties of 2D MoS₂ is synthesized. The thickness-related limit, i.e., the desired optical and electronic properties being limited to 2D single/few-layered MoS₂, was overcome in the thin film through the formation of encapsulated highly crystalline 2D MoS₂ nanosheets exhibiting a bandgap of 1.9 eV and sharp optical emission. The newly synthesized 2D-in-3D MoS₂ structure will facilitate device compatibility of 2D materials and confer superior optoelectronic device function.

Bactericidal nanoparticle coatings are very promising for hindering the indirect transmission of pathogens through cross-contaminated surfaces.

The recent emergence of bacterial pathogens resistant to most or all available antibiotics is among the major global public health problems. As indirect transmission through contaminated surfaces is a main route of dissemination for most of such pathogens, the implementation of effective antimicrobial surfaces has been advocated as a promising approach for their containment, especially in the hospital settings. However, traditional wet synthesis methods of nanoparticle-based antimicrobial materials leave a number of key points open for metal surfaces: such as adhesion to the surface and nanoparticle coalescence. Here we demonstrate an alternative route, i.e. supersonic cluster beam deposition, to obtain antimicrobial Ag nanoparticle films deposited directly on surfaces. The synthesized films are simple to produce with controlled density and thickness, are stable over time, and are shown to be highly bactericidal against major Gram positive and Gram negative bacterial pathogens, including extensively drug-resistant strains. The use of silver nanoparticle in health care is getting more widespread. The authors here describe the technique of cluster beam deposition for spraying silver on surfaces used in health care sectors. This may open a new avenue for future anti-bacterial coatings.