Wafer-Scale Production of Transition Metal Dichalcogenides and Alloy Monolayers by Nanocrystal Conversion for Large-Scale Ultrathin Flexible Electronics

Abstract

Two-dimensional (2D) transition metal dichalcogenide (TMD) layers are unit-cell thick materials with tunable physical properties according to their size, morphology, and chemical composition. Their transition of lab-scale research to industrial-scale applications requires process development for the wafer-scale growth and scalable device fabrication. Herein, we report on a new type of atmospheric pressure chemical vapor deposition (APCVD) process that utilizes colloidal nanoparticles as process-scalable precursors for the wafer-scale production of TMD monolayers. Facile uniform distribution of nanoparticle precursors on the entire substrate leads to the wafer-scale uniform synthesis of TMD monolayers with the controlled size and morphology. Composition-controlled TMD alloy monolayers with tunable bandgaps can be produced by simply mixing dual nanoparticle precursor solutions in the desired ratio. We also demonstrate the fabrication of ultrathin field-effect transistors and flexible electronics with uniformly controlled performance by using TMD monolayers.

Observation of H2 Evolution and Electrolyte Diffusion on MoS2 Monolayer by In Situ Liquid‐Phase Transmission Electron Microscopy

“…The MoS 2 monolayers grown by chemical vapor deposition (CVD) are transfer‐printed onto a glassy carbon (GC) working electrode (WE) by a surface energy‐assisted transfer method. [ 26 ] C s ‐corrected scanning transmission electron microscopy (C s ‐STEM) observations of the transferred MoS 2 show the presence of covalently bonded Mo and S atoms in the MoS 2 monolayers, confirming their successful transfer printing (Figure S1, Supporting Information). Raman spectrum and mapping data also verify the complete transfer of MoS 2 onto the microchip (Figure S2, Supporting Information).…”

Design Guidelines for Two-Dimensional Transition Metal Dichalcogenide Alloys

“…Figure can be benchmarked against limited experimental data. The same-prototype alloys Mo­(S:Se) 2 , Mo­(S:Te) 2 , and W­(S:Se) 2 have been synthesized. − W­(Se:Te) 2 is a confirmed case of polymorphism between two prototypes. This system is analyzed in detail and compared with available experimental data in the next section.…”

Bio-Inspired Electronic Eyes and Synaptic Photodetectors for Mobile Artificial Vision

“…The reported electronic eyes had limited pixel density (<1024 pixels), which was much lower than that of the conventional CMOS image sensor arrays (∼100 million pixels) because of the technical challenges in the fabrication of hemispherically curved image sensor arrays with rigid and brittle materials [76], [77]. Innovations in intrinsically soft materials [78], [79] with excellent electrical/optical properties (e.g., 2-D materials [80], [81]) can be used to fabricate high-density curved image sensor arrays. Furthermore, a highly integrated circuit design, in which individual pixels can be individually addressed, is required to enable the high-resolution image acquisition.…”