@article{atanasov_kalanyan_parsons_2016, title={Inherent substrate-dependent growth initiation and selective-area atomic layer deposition of TiO2 using "water-free" metal-halide/metal alkoxide reactants}, volume={34}, ISSN={["1520-8559"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000375115800049&KeyUID=WOS:000375115800049}, DOI={10.1116/1.4938481}, abstractNote={Titanium dioxide atomic layer deposition (ALD) is shown to proceed selectively on oxidized surfaces with minimal deposition on hydrogen-terminated silicon using titanium tetrachloride (TiCl4) and titanium tetra-isopropoxide [Ti(OCH(CH3)2)4, TTIP] precursors. Ex situ x-ray photoelectron spectroscopy shows a more rapid ALD nucleation rate on both Si–OH and Si–H surfaces when water is the oxygen source. Eliminating water delays the oxidation of the hydrogen-terminated silicon, thereby impeding TiO2 film growth. For deposition at 170 °C, the authors achieve ∼2 nm of TiO2 on SiO2 before substantial growth takes place on Si–H. On both Si–H and Si–OH, the surface reactions proceed during the first few TiCl4/TTIP ALD exposure steps where the resulting products act to impede subsequent growth, especially on Si–H surfaces. Insight from this work helps expand understanding of “inherent” substrate selective ALD, where native differences in substrate surface reaction chemistry are used to promote desired selective-area growth.}, number={1}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Atanasov, Sarah E. and Kalanyan, Berc and Parsons, Gregory N.}, year={2016}, month={Jan} } @article{kim_atanasov_lemaire_lee_parsons_2015, title={Platinum-Free Cathode for Dye-Sensitized Solar Cells Using Poly(3,4-ethylenedioxythiophene) (PEDOT) Formed via Oxidative Molecular Layer Deposition}, volume={7}, ISSN={["1944-8244"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000350193000002&KeyUID=WOS:000350193000002}, DOI={10.1021/am5084418}, abstractNote={Thin ∼ 20 nm conformal poly(3,4-ehylenedioxythiophene) (PEDOT) films are incorporated in highly conductive mesoporous indium tin oxide (m-ITO) by oxidative molecular layer deposition (oMLD). These three-dimensional catalytic/conductive networks are successfully employed as Pt-free cathodes for dye-sensitized solar cells (DSSCs) with open circuit voltage equivalent to Pt cathode devices. Thin and conformal PEDOT films on m-ITO by oMLD create high surface area and efficient electron transport paths to promote productive reduction reaction on the PEDOT film. Because of these two synergetic effects, PEDOT-coated m-ITO by oMLD shows power conversion efficiency, 7.18%, comparable to 7.26% of Pt, and higher than that of planar PEDOT coatings, which is 4.85%. Thus, PEDOT-coated m-ITO is an exceptional opportunity to compete with Pt catalysts for low-cost energy conversion devices.}, number={7}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Kim, Do Han and Atanasov, Sarah E. and Lemaire, Paul and Lee, Kyoungmi and Parsons, Gregory N.}, year={2015}, month={Feb}, pages={3866–3870} } @article{kalanyan_lemaire_atanasov_ritz_parsons_2016, title={Using Hydrogen To Expand the Inherent Substrate Selectivity Window During Tungsten Atomic Layer Deposition}, volume={28}, ISSN={["1520-5002"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000368322600017&KeyUID=WOS:000368322600017}, DOI={10.1021/acs.chemmater.5b03319}, abstractNote={Area-selective thin film deposition is expected to be important in achieving sub-10 nm semiconductor devices, enabling feature patterning, alignment to underlying structures, and edge definition. Atomic layer deposition (ALD) offers advantages over common chemical vapor deposition methods, such as precise thickness control and excellent conformality. Furthermore, several ALD processes show inherent propensity for substrate-dependent nucleation. For example, tungsten ALD using SiH4 (or Si2H6) and WF6 is more energetically favorable on Si than on SiO2, but selectivity is often lost after several ALD cycles. We show that modifying the W ALD process chemistry can decrease the W nucleation rate on SiO2, thereby expanding the ALD “selectivity window”. Specifically, we find that adding H2 during the WF6 dose step helps passivate SiO2 against W nucleation without modifying W growth on silicon. Surface characterization confirms that H2 promotes fluorine passivation of SiO2, likely through surface reactions with HF...}, number={1}, journal={CHEMISTRY OF MATERIALS}, author={Kalanyan, Berc and Lemaire, Paul C. and Atanasov, Sarah E. and Ritz, Mariah J. and Parsons, Gregory N.}, year={2016}, month={Jan}, pages={117–126} } @article{atanasov_losego_gong_sachet_maria_williams_parsons_2014, title={Highly Conductive and Conformal Poly(3,4-ethylenedioxythiophene) (PEDOT) Thin Films via Oxidative Molecular Layer Deposition}, volume={26}, ISSN={["1520-5002"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000337199400019&KeyUID=WOS:000337199400019}, DOI={10.1021/cm500825b}, abstractNote={This work introduces oxidative molecular layer deposition (oMLD) as a chemical route to synthesize highly conductive and conformal poly(3,4-ethylenedioxythiophene) (PEDOT) thin films via sequential vapor exposures of molybdenum(V) chloride (MoCl5, oxidant) and ethylene dioxythiophene (EDOT, monomer) precursors. The growth temperature strongly affects PEDOT’s crystalline structure and electronic conductivity. Films deposited at ∼150 °C exhibit a highly textured crystalline structure, with {010} planes aligned parallel with the substrate. Electrical conductivity of these textured films is routinely above 1000 S cm–1, with the most conductive films exceeding 3000 S cm–1. At lower temperatures (∼100 °C) the films exhibit a random polycrystalline structure and display smaller conductivities. Compared with typical electrochemical, solution-based, and chemical vapor deposition techniques, oMLD PEDOT films achieve high conductivity without the need for additives or postdeposition treatments. Moreover, the sequent...}, number={11}, journal={CHEMISTRY OF MATERIALS}, author={Atanasov, Sarah E. and Losego, Mark D. and Gong, Bo and Sachet, Edward and Maria, Jon-Paul and Williams, Philip S. and Parsons, Gregory N.}, year={2014}, month={Jun}, pages={3471–3478} } @article{zhao_losego_lemaire_williams_gong_atanasov_blevins_oldham_walls_shepherd_et al._2014, title={Highly adsorptive, MOF-functionalized nonwoven fiber mats for hazardous gas capture enabled by atomic layer deposition}, volume={1}, number={4}, journal={Advanced Materials Interfaces}, author={Zhao, J. J. and Losego, M. D. and Lemaire, P. C. and Williams, P. S. and Gong, B. and Atanasov, S. E. and Blevins, T. M. and Oldham, C. J. and Walls, H. J. and Shepherd, S. D. and et al.}, year={2014} } @article{atanasov_oldham_slusarski_taggart-scarff_sherman_senecal_filocamo_mcallister_wetzel_parsons_2014, title={Improved cut-resistance of Kevlar (R) using controlled interface reactions during atomic layer deposition of ultrathin (< 50 angstrom) inorganic coatings}, volume={2}, ISSN={["2050-7496"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000342763300022&KeyUID=WOS:000342763300022}, DOI={10.1039/c4ta03662j}, abstractNote={Conformal atomic layer deposition (ALD) of Al2O3 and TiO2 thin films on Kevlar®, poly(p-phenylene terephthalamide) (PPTA) fibers at 50 and 100 °C affects the fiber cut resistance. Systematic studies of ALD coatings between 10 to 400 A thick formed at 50 and 100 °C revealed excellent conformality, and trends in cutting performance depended on materials and process details. A 50 A/50 A TiO2/Al2O3 bilayer formed at 50 °C increased cut resistance of PPTA by 30% compared to untreated fiber materials. In situ infrared analysis shows that trimethylaluminum (TMA) Al2O3 precursor reacts sub-surface with PPTA and tends to degraded mechanical performance. The TiCl4 TiO2 precursor reacts to form a barrier that limits TMA/PPTA interactions, allowing a harder Al2O3 layer to form on top of TiO2. The thin ALD coatings do not substantially affect durability, flexibility, or weight of the PPTA, making ALD a potentially viable means to enhance the protective properties of Kevlar and other polymer fiber systems.}, number={41}, journal={JOURNAL OF MATERIALS CHEMISTRY A}, author={Atanasov, Sarah E. and Oldham, Christopher J. and Slusarski, Kyle A. and Taggart-Scarff, Joshua and Sherman, Shalli A. and Senecal, Kris J. and Filocamo, Shaun F. and McAllister, Quinn P. and Wetzel, Eric D. and Parsons, Gregory N.}, year={2014}, month={Nov}, pages={17371–17379} } @misc{parsons_atanasov_dandley_devine_gong_jur_lee_oldham_peng_spagnola_et al._2013, title={Mechanisms and reactions during atomic layer deposition on polymers}, volume={257}, ISSN={["1873-3840"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000327915000012&KeyUID=WOS:000327915000012}, DOI={10.1016/j.ccr.2013.07.001}, abstractNote={There is significant growing interest in atomic layer deposition onto polymers for barrier coatings, nanoscale templates, surface modification layers and other applications. The ability to control the reaction between ALD precursors and polymers opens new opportunities in ALD materials processing. It is well recognized that ALD on many polymers involves subsurface precursor diffusion and reaction which are not encountered during ALD on solid surfaces. This article reviews recent insights into chemical reactions that proceed during ALD on polymers, with particular focus on the common Al2O3 reaction sequence using trimethyl aluminum (TMA) and water. We highlight the role of different polymer reactive groups in film growth, and how the balance between precursor diffusion and reaction can change as deposition proceeds. As a strong Lewis acid, TMA forms adducts with Lewis base sites within the polymer, and the reactions that proceed are determined by the neighboring bond structure. Moreover, the Lewis base sites can be saturated by TMA, producing a self-limiting half-reaction within a three-dimensional polymer, analogous to a self-limiting half-reaction commonly observed during ALD on a solid planar surface.}, number={23-24}, journal={COORDINATION CHEMISTRY REVIEWS}, author={Parsons, Gregory N. and Atanasov, Sarah E. and Dandley, Erinn C. and Devine, Christina K. and Gong, Bo and Jur, Jesse S. and Lee, Kyoungmi and Oldham, Christopher J. and Peng, Qing and Spagnola, Joseph C. and et al.}, year={2013}, month={Dec}, pages={3323–3331} } @article{loebl_oldham_devine_gong_atanasov_parsons_fedkiw_2013, title={Solid Electrolyte Interphase on Lithium-Ion Carbon Nanofiber Electrodes by Atomic and Molecular Layer Deposition}, volume={160}, ISSN={["1945-7111"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000326905000006&KeyUID=WOS:000326905000006}, DOI={10.1149/2.020311jes}, abstractNote={Carbon nanofibers were coated with Al2O3 by atomic layer deposition (ALD) or with an alumina-organic hybrid thin film layer by molecular layer deposition (MLD) to produce an artificial solid electrolyte interphase (SEI) prior to use as a lithium-ion battery electrode. The elemental composition of the materials was investigated using energy dispersive X-ray spectroscopy (EDX) and inductively coupled plasma mass spectrometry (ICP-MS). A coating of ten Al2O3 layers reduced the lithium lost to the SEI formation from 359 to 291 mAh/g (24%) during the first charge. These same cells possessed 370 mAh/g of stable reversible capacity when tested at low current density (25 mA/g), similar to uncoated material. At increased currents, Al2O3 films of either ten or twenty layers lowered the capacity retention when compared with uncoated materials. When compared to the ALD material, films deposited by MLD resulted in less improvement to reversible capacity and a greater loss of reversible capacity. These results indicate the use of ALD to create a new electrode surface and mitigate the Li losses to SEI formation may be a viable method of addressing the challenges associated with high-surface area electrode materials.}, number={11}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={Loebl, Andrew J. and Oldham, Christopher J. and Devine, Christina K. and Gong, Bo and Atanasov, Sarah E. and Parsons, Gregory N. and Fedkiw, Peter S.}, year={2013}, pages={A1971–A1978} }