A balancing act: Optimizing free chlorine contact time to minimize iodo-DBPs, NDMA, and regulated DBPs in chloraminated drinking water.

Many drinking water treatment plants in the U.S. have switched from chlorination to chloramination to lower levels of regulated trihalomethane (THM) and haloacetic acid (HAA) disinfection byproducts (DBPs) in drinking water and meet the current regulations.

Conformal Growth of Nanometer-Thick Transition Metal Dichalcogenide TiS -NbS Heterostructures over 3D Substrates by Atomic Layer Deposition: Implications for Device Fabrication.

The scalable and conformal synthesis of two-dimensional (2D) transition metal dichalcogenide (TMDC) heterostructures is a persisting challenge for their implementation in next-generation devices. In this work, we report the synthesis of nanometer-thick 2D TMDC heterostructures consisting of TiS -NbS on both planar and 3D structures using atomic layer deposition (ALD) at low temperatures (200-300 °C). To this end, a process was developed for the growth of 2D NbS by thermal ALD using (-butylimido)-tris-(diethylamino)-niobium (TBTDEN) and HS gas.

Probing the Origin and Suppression of Vertically Oriented Nanostructures of 2D WS Layers.

Two-dimensional (2D) layered transition metal dichalcogenides (TMDs) such as WS are promising materials for nanoelectronic applications. However, growth of the desired horizontal basal-plane oriented 2D TMD layers is often accompanied by the growth of vertical nanostructures that can hinder charge transport and, consequently, hamper device application. In this work, we discuss both the formation and suppression of vertical nanostructures during plasma-enhanced atomic layer deposition (PEALD) of WS.

Low-Temperature Phase-Controlled Synthesis of Titanium Di- and Tri-sulfide by Atomic Layer Deposition.

Phase-controlled synthesis of two-dimensional (2D) transition-metal chalcogenides (TMCs) at low temperatures with a precise thickness control has to date been rarely reported. Here, we report on a process for the phase-controlled synthesis of TiS (metallic) and TiS (semiconducting) nanolayers by atomic layer deposition (ALD) with precise thickness control. The phase control has been obtained by carefully tuning the deposition temperature and coreactant composition during ALD.

Edge-Site Nanoengineering of WS by Low-Temperature Plasma-Enhanced Atomic Layer Deposition for Electrocatalytic Hydrogen Evolution.

Edge-enriched transition metal dichalcogenides, such as WS, are promising electrocatalysts for sustainable production of H through the electrochemical hydrogen evolution reaction (HER). The reliable and controlled growth of such edge-enriched electrocatalysts at low temperatures has, however, remained elusive. In this work, we demonstrate how plasma-enhanced atomic layer deposition (PEALD) can be used as a new approach to nanoengineer and enhance the HER performance of WS by maximizing the density of reactive edge sites at a low temperature of 300 °C.

Unique features of the generation-recombination noise in quasi-one-dimensional van der Waals nanoribbons.

We describe the low-frequency current fluctuations, i.e. electronic noise, in quasi-one-dimensional ZrTe3 van der Waals nanoribbons, which have recently attracted attention owing to their extraordinary high current carrying capacity.

Low-Frequency Current Fluctuations and Sliding of the Charge Density Waves in Two-Dimensional Materials.

We investigated low-frequency noise in two-dimensional (2D) charge density wave (CDW) systems, 1 T-TaS thin films, as they were driven from the nearly commensurate (NC) to incommensurate (IC) CDW phases by voltage and temperature stimuli. This study revealed that noise in 1 T-TaS has two pronounced maxima at the bias voltages, which correspond to the onset of CDW sliding and the NC-to-IC phase transition. We observed unusual Lorentzian features and exceptionally strong noise dependence on electric bias and temperature, leading to the conclusion that electronic noise in 2D CDW systems has a unique physical origin different from known fundamental noise types.

Low-Frequency Electronic Noise in Quasi-1D TaSe van der Waals Nanowires.

We report results of investigation of the low-frequency electronic excess noise in quasi-1D nanowires of TaSe capped with quasi-2D h-BN layers. Semimetallic TaSe is a quasi-1D van der Waals material with exceptionally high breakdown current density. It was found that TaSe nanowires have lower levels of the normalized noise spectral density, S/I, compared to carbon nanotubes and graphene (I is the current).

Breakdown current density in h-BN-capped quasi-1D TaSe3 metallic nanowires: prospects of interconnect applications.

We report on the current-carrying capacity of the nanowires made from the quasi-1D van der Waals metal tantalum triselenide capped with quasi-2D boron nitride. The chemical vapor transport method followed by chemical and mechanical exfoliation were used to fabricate the mm-long TaSe3 wires with the lateral dimensions in the 20 to 70 nm range. Electrical measurements establish that the TaSe3/h-BN nanowire heterostructures have a breakdown current density exceeding 10 MA cm(-2)-an order-of-magnitude higher than that for copper.

Effective purification of single-walled carbon nanotubes with reversible noncovalent functionalization.

An effective purification method for single-walled carbon nanotubes (SWNTs) based on a combination of oxidative acid treatment and reversible noncovalent functionalization with 1-pyreneacetic acid is reported. The functionalization was selective toward the nanotubes, allowing a nearly complete removal of residual metal catalysts and carbonaceous impurities. The resulting highly pure SWNTs remained solvent-dispersible, a valuable feature to potential applications that require solvent-based processing.