Surface and Interfacial Chemistry of Nanoscale Multicomponent Inorganic Films and Structures
EMSL Project ID
47950
Abstract
Transformation of small molecular precursors into inorganic solid-state compounds via solution methods has mainly focused on sol-gel techniques involving hydrolysis and condensation reactions of metal-organic compounds in bulk solutions. This method generally produces porous structures because of the difficulties in controlling the reactions leading to sol formation. As part of the National Science Foundation Center for Sustainable Materials Chemistry (CSMC), we have undertaken a revolutionary approach to forming high-quality inorganic multicomponent films where we trap reactive precursors in an aqueous-based thin film and then induce controlled condensation. These condensation reactions can be initiated through thermal, photon, and electron stimulated processes. Using these methods we have synthesized smooth, fully dense, crackfree, high-quality films of many compositions, including HfO2, ZrO2, HfO2-x(SO4)x, ZrO2-x(SO4)x, and Al4O3(PO4)2, with controlled thickness down to 8 A.(1) The functionality of the resulting materials has been demonstrated through fabrication of high-performance thin-film transistors and displays,(1b, 2) dielectric mirrors and band-pass filters,(3) diffraction and light-trapping gratings,(4) and leading-edge directly patterned nanostructures via electron-beam and extreme ultra-violet lithographies.(5) Direct nanopatterning of oxide films has also been demonstrated at length scales below 10 nm. The objective of this proposal is to further develop a fundamental understanding of the interfacial reaction mechanisms of the film formation and condensation from aqueous inorganic precursors. A molecular level understanding of the aqueous phase nucleation of film precursors, film forming processes, dehydration and annealing mechanisms, segregation, and reactivity will catalyze the design of a large family of high quality thin films with tunable composition and properties using low energy processing techniques. This proposal is well aligned with the EMSL's Science Theme on the "Science of Interfacial Phenomena"; EMSL capabilities will enable in-situ integrated approaches that combine both experimental and theoretical methods to advance our understanding of nanoscale multicomponent inorganic films and structures with applications to lithography, catalysis, photovoltaics, and energy storage.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2013-10-01
End Date
2014-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members
Related Publications
Flynn BT, RP Oleksak, S Thevuthasan, and GS Herman. 2018. "Interfacial Chemistry-Induced Modulation of Schottky Barrier Heights: In Situ Measurements of the Pt-Amorphous Indium Gallium Zinc Oxide Interface Using X-ray Photoelectron Spectroscopy." ACS Applied Materials & Interfaces 10(4):4333-4340. doi:10.1021/acsami.7b18674