Toolbox of Advanced Atomic Layer Deposition Processes for Tailoring Large-Area MoS2 Thin Films at 150 °C

Two-dimensional MoS2 is a promising material for applications, including electronics and electrocatalysis. However, scalable methods capable of depositing MoS2 at low temperatures are scarce. Herein, we present a toolbox of advanced plasma-enhanced atomic layer deposition (ALD) processes, producing wafer-scale polycrystalline MoS2 films of accurately controlled thickness. Our ALD processes are based on two individually controlled plasma exposures, one optimized for deposition and the other for modification. In this way, film properties can be tailored toward different applications at a very low deposition temperature of 150 °C. For the modification step, either H2 or Ar plasma can be used to combat excess sulfur incorporation and crystallize the films. Using H2 plasma, a higher degree of crystallinity compared with other reported low-temperature processes is achieved. Applying H2 plasma steps periodically instead of every ALD cycle allows for control of the morphology and enables deposition of smooth, polycrystalline MoS2 films. Using an Ar plasma instead, more disordered MoS2 films are deposited, which show promise for the electrochemical hydrogen evolution reaction. For electronics, our processes enable control of the carrier density from 6 × 1016 to 2 × 1021 cm–3 with Hall mobilities up to 0.3 cm2 V–1 s–1. The process toolbox forms a basis for rational design of low-temperature transition metal dichalcogenide deposition processes compatible with a range of substrates and applications

The Grizzly, November 19, 1991

Founders\u27 Day Excitement • Grizzly Network Career Day • Women\u27s Choices • Volksmarching • Louisiana Election • Service Opportunities for Students • The European Situation • Jonas Salk Addresses Founders Day Convocation • Dr. Takats Awarded the Clamer Chair • Wellness Services Proposal • U.S.G.A. Minutes • Ursinus Continues Helping Habitat • Turkey Drive Needs You • Zack: The Man, The Myth, The Statue • Hocus Pocus a Success • Ursinus Students in Community Production of Gypsy • Movie Review: Hamlet • Battle of the Bands • Rollins Rocks Lower Lounge • Branker Tours to St. Petersburg • CAB Trip to New York • Writing in Good Taste • Magic: One Trick Too Many • Letters: Faculty Members Speak Out; GALA Replies to Letter; Call for Diversity; Publishing the Truth?; Student Reaction to Ronning; Response to Black Hole ; Students React to Social Life • No More Crap! • Filling in the Black Hole • One Professor\u27s Awakening • Lady Bears End Season • Men\u27s Lacrosse Awaits Chance • Women Swimmers Wash Out Washington • Spinella Takes Over as Head Coach of Basketball Team • Dickinson Defeats the Bearshttps://digitalcommons.ursinus.edu/grizzlynews/1284/thumbnail.jp

Metal Organic Frameworks(MOFs)

UiO–66, a zirconium-based metal organic framework (MOF), was synthesized to investigate surface-level interactions. We are interested in expand- ing our understanding of MOFs and their ability to cap, trap, and store guest molecules within their porous 3-D structures, applicable for drug delivery. We hypothesize that fluorocarbon silanes will interact with UiO–66 terminal oxygen species to form strong covalent bonds. Synthesized by previously established solvothermal methods, UiO–66 crystals were incorporated in a series of experiments to investigate interfacial states and attachment strategies for capping and trapping. In vacuo heating and Ar+ sputtering experiments further supported the binding interaction between the silane and the UiO–66 itself. Analytical techniques including thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and powder X-ray diffraction (pXRD) were used to evaluate the effectiveness of developed methods. We have demonstrated that silanes attached to a UiO–66 surface provides a method for establishing monolayer chemistry that is compatible with this specific MOF family