Wafer-Scale Production of TMDs and Alloy Monolayers by Nanocrystal Precursors

Two-dimensional TMD monolayers are unit-cell thick materials with tunable physical properties depending on 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 introduce a new type of CVD process utilizing colloidal nanoparticles as process-scalable precursors for the wafer-scale production of TMD monolayers. Facile and uniform loading of nanoparticle precursors on the entire substrate enables the wafer-scale uniformity in synthesis of TMD monolayers. TMD alloy monolayers with controlled composition and resulting tunable bandgaps can be synthesized by mixing dual nanoparticle precursor solutions in a ratio. It is also demonstrated that ultrathin field-effect transistors and flexible electronics with uniformly controlled performance can be fabricated by using TMD monolayers.