Walker, Amy - University of Texas-Dallas

个人简介

1998 PhD Chemistry, University of Cambridge 1995 BA (Hons) Natural Sciences (Physics and Theoretical Physics), University of Cambridge

研究领域

The ultimate goal of Amy Walker’s research is the development of simple, robust materials for constructing complex two- and three-dimensional surfaces by manipulating interfacial chemistry. Metal/SAM, semiconductor/SAM and biomolecule/SAM structures have applications in organic electronics, sensing, catalysis, photovoltaics and optoelectronics. Her group also develops analytical techniques to probe the structures produced. The Walker group employs surface science techniques, in particular time-of-flight secondary ion mass spectrometry (TOF SIMS) and reflection absorption infrared spectroscopy (RAIRS) and calculations of molecular structure (density functional theory, DFT) in this work. TOF SIMS is a unique widely applicable technique that provides detailed information about the chemical composition of surfaces with sub-micron lateral resolution, and is used in areas from biological systems to materials science. Current research interests include: New Methods for Constructing Metallized Organic Surfaces In the area of molecular electronics, individual devices (such as diodes and memory elements) are prepared by the deposition of metals (the "contact") onto a SAM. Device-to-device variation and short device lifetimes due to small changes in the structure of these contacts are often observed. With this in mind, we are amassing a database of metal-molecule interactions to help guide the design of metallic contacts. We are also developing new metallization techniques for organic surfaces including chemical vapor deposition (CVD) and electroless deposition. Chemical Bath Deposition of Semiconductors on Organic Surfaces There is a need to develop cheap, simple methods to deposit semiconductors on organic surfaces for photovoltaic applications. With this in mind, we are investigating the reaction pathways involved in chemical bath deposition to selectively deposit inorganic nanostructures on organic thin films. Ionic Liquid Matrices and New Data Analysis Techniques for Imaging Mass Spectrometry SIMS can be used to obtain mass spectrometric images of surfaces with sub-micron resolution. However, it is often hard to obtain a large number high mass ions (m/z 500) in SIMS leading to a loss of information and degradation of the image (lateral) resolution. To overcome this, we are currently developing a new class of matrix for imaging SIMS – ionic liquids. Our results indicate that ionic liquids are very effective matrices. They are suitable for imaging applications and increase observe ion intensities by 10-100 times. SIMS images contain a lot of data – much of which is currently ignored. In collaboration with Lev Gelb’s group we are developing new data analysis techniques to extract as much information from these images as possible.

近期论文

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J.J.D. Fitzgerald, P. Kunnath, A.V. Walker, "Matrix-Enhanced Secondary Ion Mass Spectrometry (ME SIMS) Using Room Temperature Ionic Liquid Matrices", Analytical Chemistry, 82 (2010) 4413-4419. C. Zhou, A. V. Walker, "Formation of Multilayer Ultrathin Assemblies Using Chemical Lithography", Langmuir, 26 (2010) 8441-8449. P. Lu, Z. Shi, A.V. Walker, "Selective Formation of Monodisperse CdSe Nanoparticles on Functionalized Self-Assembled Monolayers Using Chemical Bath Deposition", Electrochimica Acta,DOI:10.1016/j.electacta.2010.03.054. C. Zhou, A.J. Trionfi, J.W.P. Hsu, A.V. Walker, "Electron Beam Induced Damage of Alkanethiolate Self-Assembled Monolayers (SAMs): Dependence on Monolayer Structure and Substrate Conductivity", J. Phys. Chem. C, 114 (2010) 9362â€“9369. A.V. Walker, "Building Robust and Reliable Molecular Constructs: Patterning, Metallic Contacts and Layer-by-Layer Assembly", Langmuir,26 (2010) 13778-13785. Invited Feature Article. A.V. Walker, "Mass Spectrometry: Secondary Ion Mass Spectrometry", Encyclopedia of Spectroscopy and Spectrometry, 2nd Edition, J.C. Lindon (Editor-in-Chief), Elsevier, Kidlington, Oxford, UK, 2010. C. Zhou, J.C. Jones, A.J. Trionfi, J.W.P. Hsu, A.V. Walker, "Comparison of Chemical Lithography Using Alkanethiolate Self-Assembled Monolayers on GaAs (001) and Au", Langmuir, 26 (2010) 4523â€“4528. C. Zhou, J.C. Jones, A.J. Trionfi, J.W.P. Hsu, A.V. Walker, "Electron Beam Induced Damage of Alkanethiolate Self-Assembled Monolayers Adsorbed on GaAs (001): A Static SIMS Investigation", J. Phys. Chem. C., 114 (2010) 5400â€“5409. J. Bartels, P. Lu, A.V. Walker, K.Maurer, K.D. Moeller, "Building Addressable Libraries: A Site-Selective Click Reaction Strategy for Rapidly Assembling Mass Spec Cleavable Linkers" Chem. Commun. (2009) 5573-5575. P.D. Carpenter, S. Lodha, D.B. Janes, A.V. Walker, "Structural and Electrical Characterization of Au Contacts in GaAs-Based Molecular Devices", Chem. Phys. Letts., Â 472 (2009) 220-223. G. Sun, C. Cheng, H. Fang, P. Lu, K. Zhang, A.V. Walker, J.-S. A. Taylor, K. L. Wooley, "Benzaldehyde-Functionalized Polymer Vesicles", ACS Nano, 3 (2009) 673-681. P. Lu, A.V. Walker, "Making Nanoflowerbeds: Reaction Pathways Involved in the Selective Chemical Bath Deposition of ZnS on Functionalized Alkanethiolate Self-Assembled Monolayers", ACS Nano, 3 (2009) 370-378. A. V. Walker, "Why is SIMS Underused in Chemical and Biological Analysis? Challenges and Opportunities", Anal. Chem., 80 (2008) 8865-8870. C. Chen, P. Lu, A. Walker, K. Maurer, K.D. Moeller, "Building Addressable Molecular Libraries: The Use of a Detectable, Mass Spectrometry Cleavable Linker", Electrochemical Communications, 10 (2008) 973-976. C. Zhou, K. Qi, K.L. Wooley, A.V. Walker, "Time-of-Flight Secondary Ion Mass Spectrometry, Fluorescence Microscopy and Scanning Electron Microscopy: Combined Tools for Monitoring the Process of Patterning and Layer-by-Layer Assembly of Synthetic and Biological Materials", Colloids and Surfaces B, 65 (2008) 85-91. P. Lu, K. Demirkan, R.L. Opila, A.V. Walker, "Room-Temperature Chemical Vapor Deposition of Aluminum on Alkanethiolate Self-Assembled Monolayers", J. Phys. Chem. C, 112 (2008) 2091-2098. C. Zhou, A.V. Walker, "UV Photooxidation of a Homologous Series of n-Alkanethiolate Monolayers on GaAs(001): A Static SIMS Investigation", J. Phys. Chem. C, 112 (2008) 797-805. G. Nagy, P. Lu, A.V. Walker, "An Investigation of Secondary Ion Yield Enhancement using Bin2+ (n = 1,3,5) Primary Ions", J. Am. Soc. Mass. Spec., 19 (2008) 33-45. P. Lu, A.V. Walker, "Investigation of the Mechanism of Electroless Deposition of Copper on Functionalized Alkanethiolate Self-Assembled Monolayers Adsorbed on Gold", Langmuir, 23 (2007) 12577-12582. C. Zhou, A.V. Walker, "UV Photoxidation and Photopatterning of Alkanethiolate Self-Assembled Monolayers on GaAs(001)", Langmuir 23 (2007) 8876-8881.