Retraction fibers (RFs) determine orientation of the cell division axis and guide the spreading of daughter cells. Long and unidirectional RFs, which are especially apparent during mitosis of cells in three-dimensional (3D) environments, enable improved control over cell fate, following division. However, 3D gel environments lack the cues necessary for...
The integration of amorphous zinc tin oxide (ZTO) into crossbar memristor device structures has been investigated where asymmetric devices were fabricated with Al (top) and Pt (bottom) electrodes. The authors found that these devices had reproducible bipolar resistive switching with high switching ratios >10(4) and long retention times of >10(4)...
The authors present a facile, low-cost methodology to fabricate high-performance In-Ga-Zn-O (IGZO) bottom contact, bottom gate thin-film transistors (TFTs) by soft lithography. The IGZO channel and indium tin oxide (ITO) source and drain were patterned using microcontact printing of an octadecylphosphonic acid self-assembled monolayer (SAM). A polymer stamp was used...
Biophysical studies of the interaction of peptides with model membranes provide a simple yet effective approach to understand the transport of peptides and peptide based drug carriers across the cell membrane. Herein, the authors discuss the use of self-assembled monolayers fabricated from the full membrane-spanning thiol (FMST) 3-((14-((40-((5-methyl-1-phenyl-35-(phytanyl)oxy- 6,9,12,15,18,21,24,27,30,33,37-undecaoxa-2,3-dithiahenpentacontan-51-yl)oxy)-[1,10-biphenyl]-4- yl)oxy)tetradecyl)oxy)-2-(phytanyl)oxy...
A comparison was made of Al₂O₃ films deposited on Si via prompt inorganic condensation (PIC)
and atomic layer deposition (ALD). Current–voltage measurements as a function of annealing
temperature indicate that the solution-processed PIC films, annealed at 500°C, exhibit lower
leakage and roughly equivalent breakdown strength in comparison to ALD films....
Bismuth oxide thin films were deposited by atomic layer deposition using Bi(OCMe₂ [superscript i]Pr)₃ and H₂O
at deposition temperatures between 90 and 270°C on Si₃N₄, TaN, and TiN substrates. Films were
analyzed using spectroscopic ellipsometry, x-ray diffraction, x-ray reflectivity, high-resolution
transmission electron microscopy, and Rutherford backscattering spectrometry. Bi₂O₃ films
deposited...
Metal–insulator–metal diodes with Nb₂O₅ and Ta₂O₅ insulators deposited via atomic layer deposition are investigated. For both Nb₂O₅ and Ta₂O₅, the dominant conduction process is established as Schottky emission at small biases and Frenkel–Poole emission at large biases. Fowler–Nordheim tunneling is not found to play a role in determining current versus...
Cellulose nanocrystal (CNC) aerogels are coated with thin conformal layers of Al₂O₃ using
atomic layer deposition to form hybrid organic/inorganic nanocomposites. Electron probe
microanalysis and scanning electron microscopy analysis indicated the Al₂O₃ penetrated more
than 1500 μm into the aerogel for extended precursor pulse and exposure/purge times. The
measured profile...
Low temperature atomic layer deposition (ALD) of monolayer to few layer MoS₂ uniformly across 150mm diameter SiO₂/Si and quartz substrates is demonstrated. Purge separated cycles of MoCl5 and H₂S precursors are used at reactor temperatures of up to 475 °C. Raman scattering studies show clearly the in-plane (E¹₂g) and out-of-plane...
The clotting protein von Willebrand factor (VWF) binds to platelet receptor glycoprotein Ibα (GPIbα) when VWF is activated by chemicals, high shear stress, or immobilization onto surfaces. Activation of VWF by surface immobilization is an important problem in the failure of cardiovascular implants, but is poorly understood. Here, the authors...
Transparent conductive oxides (TCO) are at the forefront of technology with their uses in
touch screen phones and televisions, solar cells and more. Titanium dioxide and tin dioxide are two TCOs that have been studied in depth on their own, so to further explore these TCOs, this project focuses on...
Organotin clusters have attracted notable attention for use as inorganic photoresists. This dissertation discerns dimeric and dodecameric organotin clusters, [(n-C₄H₉Sn)(OH)(H₂O)Cl₂]₂ (Sn₂) and [(n-C₄H₉Sn)₁₂O₁₄ (OH)₆ ]+ (Sn₁₂), both of which are stable hydrolysis and condensation products of n-C₄H₉SnCl₃. This work identifies Sn₂ as a superior precursor choice for solution deposition of...
The thermal oxidation of submicron metallic Zn particles was studied as a method to form nanostructured ZnO films. The particles used for this work were characterized by electron microscopy, x ray diffraction, and thermal analysis to evaluate the Zn-ZnO core shell structure, surface morphology, and oxidation characteristics. Significant nanostructural changes...
Heterogeneous catalysis modulates the rate and selectivity of reaction processes by
stabilizing a series of intermediate states on solid surfaces, facilitating the production
of many commodity chemicals modern society relies upon. Conventional, thermal
catalytic processes—conducted at elevated temperatures and pressures—source
thermal, mechanical, and chemical potential energy from carbon-hydrogen bonds—
combustion...
Molybdenum disulfide (MoS2) has potential applications as a low-cost catalyst for the hydrogen evolution reaction (HER). Defects on MoS2, such as edge sites and sulfur vacancies, are known to be the major active sites for HER. Controlling the formation of these defects allows for the enhancement in reactivity of MoS2...
There have been many attempts to characterize and mimic natural fluid-based adhesive systems. However, very few of these studies have examined surface or interfacial interactions between adhesive and substrate. Furthermore, until now no study has used a combination of surface analytical and kinematic techniques to determine the precise chemical mechanisms...
The continuous development of higher performing battery materials has emerged in parallel with the development of new manufacturing processes. Nanomaterials are one solution to addressing the cycling and performance challenges that limit existing battery cells. However, many of the methods used today for nanomaterial synthesis are high temperature batch methods...
Amorphous metal thin films (AMTFs) are of growing interest due to their unique mechanical properties and chemical stability. AMTFs have an advantage over polycrystalline metal films due to the lack of grain boundaries which gives AMTFs added durability and relatively smoother surfaces. For this reason, AMTFs have been investigated as...
The oxidation of carbon monoxide (CO) to carbon dioxide (CO2) is ubiquitous throughout many industrial processes and is a common probe reaction used to help understand catalytic systems in research settings. The reaction is essential in power generation and transportation exhaust gas treatment technologies to ensure environmental safety, because CO...
Flexible Electronics is a fast developing technology that is set to revamp and revolutionize conventional electronics through the development of devices that are easily conformable to surfaces of any arbitrary geometry. Such devices would have vast applications in areas where the rigidity of traditional silicon based electronics is undesirable, such...
This paper describes the construction and use of a cost-effective custom-built atomic layer deposition (ALD) system, as well as the investigation of aluminum oxide atomic layer deposition using trimethylaluminum and water. For this research, a cost-effective ALD system was constructed for less than $8,000 using existing parts that were given...
Nonthermal electrical plasmas can allow energy intensive reactions to occur without the use of high operating temperatures or pressures. This is because the collisions of electrons accelerated through an electric field with molecules is the cause of reactions as opposed to thermal collisions between molecules. In this study, the production...
In Intense Pulsed Light (IPL) sintering, pulsed large-area visible light from a xenon lamp is absorbed by nanoparticle films or patterns and converted to heat, resulting in rapid sintering of the nanoparticles. This work experimentally characterizes IPL sintering of silver nanoparticle films. A newly observed turning point in the evolution...
The phases of transition alumina are scientifically interesting due to their high specific surface area, favorable acid/ base characteristics, and chemical and hydrothermal stability which make this metallic oxide a prime candidate for use as a support for metallic nanoparticles (NPs) in heterocatalysis. Interactions at alumina/Pt interfaces are important for...
Cobalt germanides have been widely studied as semiconductor contact materials, but recent theoretical studies suggest that they may also be excellent catalysts for methane steam reforming with stabilities and activities comparable to noble metal catalysts. In order to study the catalytic activity of cobalt germanides, it is critical to first...
Immobilized proteins are integral components of a number of important technologies, including the principal component of many biosensors, as functional coatings in various implants, as catalysts is industrial biosynthesis, and as the building blocks of next-generation nanotechnologies. Despite their ubiquity, relatively little is known about the processes that shape immobilized...
Additive manufacturing has become a promising method for the fabrication of inexpensive, green, flexible sensors and electronics. Printed electronics on low- temperature substrates are very appealing for the flexible hybrid electronics market for their use in disposable and biocompatible electronic applications and in areas like packaging, wearables, and consumer electronics....
In this work, colloidal PbSe quantum dots (QDs) are shown to be synthesized in a controlled manner by changing the growth time and reaction temperature in a microwave synthesis method. It is explained why quantum dots make such a unique material to create electronic devices and the specific benefits that...
Water electrolysis plays a pivotal role in achieving a green hydrogen economy by sourcing electricity from intermittent renewable sources. However, the efficiency of the electrolysis process is limited by the sluggish oxygen evolution reaction (OER) kinetics, whereas the kinetics of the hydrogen evolution reaction (HER) are more facile. This thesis...
Due to the high cost of precursor materials, complex oxides of 4d and 5d transition metals are under-studied compared to their 3d counterparts. Recent studies have shown that oxides containing heavier transition metals can exhibit exotic electronic states due to presence of strong spin-orbit coupling. The goal of this dissertation...
A unique microreactor-assisted nanomaterial synthesis and printing process was studied for the fabrication of patterned metal oxide nanostructured thin films. The process uses a continuous flow microreactor to control and generate a reactive chemical flux that was transported to a patterned microfluidic channel. The microreactor-assisted nanomaterial synthesis process can generate...
Polyoxometalates are a rapidly growing class of discrete metal oxide clusters with a wide range of applications including functional materials. These anionic clusters of the group V and VI transition metals are inexpensive and non-toxic. Within group V polyoxometalates, niobium and tantalum chemistry has been underdeveloped owing to their unique...
Aerogels are interesting material systems with outstanding properties such as low density, high surface area, and low thermal conductivity. They can be used for a variety of applications, such as solar cells, sensors, or catalysts. Additionally they provide a unique model system to study the properties of small particles. Cellulose...
Polyoxometalates (POMs) are anions consisting of three or more early transition metals ™ (Gr V and VI) oxoanions (in their highest oxidation state) linked together by a shared oxygen bond to form a 3D framework. Polyoxometalates (POMs) are a rapidly growing class of metal oxo clusters with a wide range...
In this dissertation, the structural properties, thermodynamics and defect behavior of amorphous metal oxides and polyoxometalates are studied. Amorphous metal oxides have many applications, most notably as a semiconducting material used as the active matrix of thin film transistors. Alas, the amorphous nature of these materials makes studying them rather...
The optical and electronic properties of amorphous oxide thin films depend crucially on chemical composition, and deposition process variations which give rise to sub-gap defect states. Consequently, there is a need for a reliable, high-throughput method to extract sub-gap defect densities of states in amorphous oxide thin films. We present...
The photophysical properties of two-dimensional (2D) layered van der Waals (vdW) materials, and their heterostructures are manifestly distinct from crystalline bulk materials. Recently, the discovery of new 2D vdW materials and strongly-bound interlayer excitons in these materials has created a new branch in nanoscience. As such, there are a number...
Metal-insulator-metal (MIM) tunnel devices have been proposed for high speed applications such as hot electron transistors, IR detectors, optical rectennas for IR energy harvesting, and backplanes for LCDs. The majority of these applications require highly asymmetric and non-linear current versus voltage (I-V) behavior at low applied voltages and ultra-high frequencies....
Based on experimental investigations the present study evaluates flow instability and
void fraction in a fractal-like branching microchannel network with rectangular cross-section. The hydraulic diameter of the channels ranged from 308μm at the inlet to 143μm at the outlet. The flow network used is characterized by set branching ratios for...