NER: Supercritical carbon dioxide assisted deposition and Interfacial properties of metal oxide thin films.
NSF Nanoscale Exploratory Research PI: Prof. Theodosia Gougousi Department of Physics, University of Maryland Baltimore County
This proposal was received in response to Nanoscale Science and Engineering initiative, NSF 04-043, category NER. The objective of this research is to investigate whether salvation forces from supercritical fluids can be used to enable deposition of thin insulating films with good interfacial properties. Mainstream vacuum-based deposition techniques are usually mass transport limited by the low vapor pressure of the precursors, and proceed through a chemical reaction on a heated substrate (>300 C), high pressure process that uses soluble organic peroxides and metal organic precursors to a surface, b) provide energy for film formation, and c) accomplish reaction by-product removal.
This research is important because fabrication of future nanoscale devise may entail formation of multilayer miniaturized structures on patterned surfaces, and may involve depositions on microporous structures and on temperature sensitive materials such as organic or biological molecules. Nanoscale materials have different properties from bulk materials because the proportion of surfaces and interfaces in significant compared to the volume. As a result, interface phenomena are important because they define the operation of nanodevices. Conventional chemical vapor deposition techniques are unable to deposit uniform films on deep, narrow wells or inside porous materials. They involve high temperature steps that augment undesirable interface reactivity and would either destroy or render inactive most organic/biological molecules. Processing in supercritical carbon dioxide may provide a low temperature avenue for the deposition of uniform, high purity, thin films, with desirable interfacial properties and quality on patterned surfaces or microporpous structures, impacting technological fields such nanoelectronics, molecular electronics, biocatalysis, NEMS and bioNEMS. Students will be trained in these novel approaches providing the human infrastructure required for the wider implementation of these techniques.
