Browsing by Author "Jacqueline Krim, Member"

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Atomistic Insights into the Structure and Dynamics of Hydration Layers of the Detonation Nanodiamond with various Surface Chemistries in the Aqueous Solution of Inorganic Salts.
(2020-06-05) Saberi Movahed, Farshad; Donald Brenner, Chair; Brian Reich, Member; Douglas Irving, Member; Jacqueline Krim, Member
Effects of Strain Relaxation in SiGe Growth on Uniquely Oriented Si Substrates
(2002-02-11) Ware, Morgan Ellison; Robert Nemanich, Chair; Christopher Roland, Member; Dennis Maher, Member; Jacqueline Krim, Member
The growth of SiGe epitaxial layers on Si has become the model system for studies of strain layer epitaxy. In this research solid source molecular beam epitaxy was employed to prepare the epitaxial films, and we have employed methods to quantitatively measure the strain in the film (Raman spectroscopy), the interface misfit structure (transmission electron microscopy), and the surface morphology (atomic force microscopy). This thesis explores the formation and subsequent relaxation of strain in SiGe films grown on substrates, which were identified to have unique stable surface structures. The substrates, with crystallographic surface orientations between (001) and (111), are characterized by atomic steps and facets aligned with the [-110] direction. Specifically, the substrates studied have surface normals rotated by 10 and 22 degrees from [001] representing a (118), and (114) - (113) faceted surface respectively. The interface misfit array on the (001) surface that is characterized by two orthogonal arrays was found to form in three unique directions on substrates with a large off-axis tilt. These dislocations align with the predicted intersections of the [111] planes with the substrates, and we derived an expression that describes the observations. We estimated the relaxation of a layer by determining dislocation densities in the TEM images. Notably, the relaxation will vary depending on the Burgers vector chosen to represent the dislocation arrays. A direct correlation was found with the pattern of misfit dislocations and the surface morphology of relaxed films grown on these off-axis substrates. The long range surface corrugations align well with the same three directions as the dislocations indicating that the formation of the misfit dislocations cause this alignment. Our studies of the strain showed that the strain relaxation increased linearly with film thickness indicating a kinetic process as opposed to a sudden plastic relaxation by misfit dislocation formation. In combining these results, we find that only a fraction of the observed strain relaxation can be accounted for with the observed density of misfit arrays. The organization and presence of the surface morphology indicates that the surface morphology also significantly contributes to the strain relaxation both in the coherently strained films and in the partially relaxed structures.
Gels and Oil-in-Water Emulsions: a Stepwise, Rheology- and Tribology-Focused Approach.
(2020-03-23) Vasconcelos de Farias, Barbara; Saad Khan, Chair; Jan Genzer, Member; Michael Dickey, Member; Orlin Velev, Member; Chien Ching Lilian Hsiao, Member; Jacqueline Krim, Member
Instabilities in Oxidizing Liquid Eutectic Gallium-Indium.
(2022-03-24) Hillaire, Keith Daniel; Karen Daniels, Chair; Michael Dickey, Member; Daniel Dougherty, Member; Jacqueline Krim, Member
Investigating Granular Structure with Spatial and Temporal Methods.
(2012-10-22) Owens, Eli Thomas; Karen Daniels, Chair; Michael Shearer, Member; Keith Weninger, Member; Jacqueline Krim, Member
A Low-Power, High Performance MEMS-based Switch Fabric
(2001-10-17) Duewer, Bruce Eliot; Paul D. Franzon, Chair; Thomas M. Conte, Member; Wentai Liu, Member; Jacqueline Krim, Member
An approach with the potential for building large low power high performance crossbar networks is presented. Thin film polysilicon MEMS devices are developed to provide crosspoints. These devices are vertically moving plates that serve as variable capacitors. Addressing of large arrays using 2n rather than n-squared lines despite no active circuitry on the MEMS chips is facilitated by bistable device operation. Derivations of equations for bistable device operation are presented. Low power operation is possible as the devices are electrostatically controlled and are stationary except during reconfiguration. Early devices are fabricated using the MUMPS process. The bistability and array addressability properties are demonstrated. The substrate effect on device operation is measured and modeled; methods for utilizing the substrate effect to tune device operation are presented. Later devices are fabricated using the SUMMiT process. Changes in the SUMMiT design rules to increase allowable vertical motion range are proposed and designs using them fabricated. S-parameter characteristics of devices in both 'on' and `off' states are measured. Addition of metallization after chip fabrication and release is necessary to lower the resistance of interconnect. A self masking method for applying this metallization allowing for decreased resistance at line crossings is proposed. This method is tested using each of sputtering and evaporation as the deposition technique for a gold and adhesion layer stack. Effectiveness of the method with each technique is evaluated. Chips suitable for providing high voltage control for large MEMS arrays are fabricated in a 2um feature size CMOS process. Architectures suitable for building large crossbars employing variable capacitor arrays are discussed. Optimization of hybrid CMOS/MEMS Clos arrays on the basis of criteria other than minimization of crosspoints is discussed. Array sizings to provide 192*192 and 256*256 crossbars are presented, and software examples for sizing and controlling Clos networks are provided. Evaluation of the suitability of the MEMS devices developed for use as digital or broadband crosspoints is evaluated, and potential future directions are proposed.
Micro- and Macro-Scale Analysis of Frictional Interaction between Human Skin and Woven Fabrics.
(2021-06-01) Baby, Ruksana; Kavita Mathur, Chair; Jacqueline Krim, Member; Emiel DenHartog, Member; Lori Rothenberg, Member
Molecular Model for the Interaction of Charged Nano-Particles with Metal Surfaces.
(2019-11-04) Su, Liangliang; Donald Brenner, Chair; Jacqueline Krim, Member; Christopher Roland, Member; Alexej Smirnov, Member
New Applications of Sequential Experimental Design.
(2018-11-06) Winkel, Munir Ahmed; Brian Reich, Co-Chair; Jonathan Stallrich, Co-Chair; Joseph Guinness, Member; Elon Ison, Graduate School Representative; Jacqueline Krim, Member
Scanning Tunneling Microscopy and Spectroscopy of Metal-Organic Interfaces for Electronics and Spintronic Applications.
(2012-03-23) Wang, Zhengang; Daniel Dougherty, Chair; David Shultz, Member; John Rowe, Member; Marco Buongiorno-Nardelli, Member; Jacqueline Krim, Member