Area-Selective Atomic Layer Deposition of Two-Dimensional WS Nanolayers.

With downscaling of device dimensions, two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) such as WS are being considered as promising materials for future applications in nanoelectronics. However, at these nanoscale regimes, incorporating TMD layers in the device architecture with precise control of critical features is challenging using current top-down processing techniques. In this contribution, we pioneer the combination of two key avenues in atomic-scale processing: area-selective atomic layer deposition (AS-ALD) and growth of 2D materials, and demonstrate bottom-up processing of 2D WS nanolayers.

Large area, patterned growth of 2D MoS and lateral MoS-WS heterostructures for nano- and opto-electronic applications.

The patterned growth of transition metal dichalcogenides (TMDs) and their lateral heterostructures is paramount for the fabrication of application-oriented electronics and optoelectronics devices. However, the large scale patterned growth of TMDs remains challenging. Here, we demonstrate the synthesis of patterned polycrystalline 2D MoS thin films on device ready SiO/Si substrates, eliminating any etching and transfer steps using a combination of plasma enhanced atomic layer deposition (PEALD) and thermal sulfurization.

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.

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.