Nanoscience and Nanotechnology Commons^™

Highly Transmissive Scalable Colored Coatings For Architectural Photovoltaic Panels, Akbar Ali Syed

Electrical & Computer Engineering Theses & Dissertations

Highly transmissive coatings were developed by fabricating thin films using SiO₂ and SiO₂/TiO₂ core/shell nanoparticles on glass substrates and on the photovoltaic cell glass covers. This coating is to maintain an attractive color appearance of the exterior surface for architecturally integrated photovoltaics and can be coated on fabricated photovoltaic panels. The color and optical properties of the nanoparticle coating was investigated for different nanoparticle diameters of 200-400 nm for SiO₂ nanoparticles and core/shell nanoparticles having SiO₂/TiO₂ structure with 300 ± 11 nm diameter, and SiO₂/TiO₂/SiO₂ structure with …

Laser-Spark Multicharged Ion Implantation System ‒ Application In Ion Implantation And Neural Deposition Of Carbon In Nickel (111), Oguzhan Balki

Electrical & Computer Engineering Theses & Dissertations

Carbon ions generated by ablation of a carbon target using an Nd:YAG laser pulse (wavelength λ = 1064 nm, pulse width τ = 7 ns, and laser fluence of 10-110 J/cm²) are characterized. Time-of-flight analyzer, a three-mesh retarding field analyzer, and an electrostatic ion energy analyzer are used to study the charge and energy of carbon ions generated by laser ablation. The dependencies of the ion signal on the laser fluence, laser focal point position relative to target surface, and the acceleration voltage are described. Up to C⁴⁺ are observed. When no acceleration voltage is applied between …

Enhancement Of Thermoelectric Properties Of Ald Synthesized Pbte And Pbse By Phonon Engineering, Xin Chen

Electrical & Computer Engineering Theses & Dissertations

Thermoelectrics is a green renewable energy technology that plays an important role in power generation due to its potential in generating electricity out of waste heat. The main challenge for the development of thermoelectrics is its low conversion efficiency. One key strategy to improve conversion efficiency is focused on reducing the thermal conductivity of thermoelectric materials. In this thesis, the novel phononic engineering concept was implemented by conformal ALD deposition of PbTe, PbSe thermoelectric films, and PbTe/PbSe nanolaminates on patterned silicon substrates in order to improve the thermoelectric performance of the thermoelectric films. The silicon substrates were lithographically patterned with …

The Efficacy Of Programming Energy Controlled Switching In Resistive Random Access Memory (Rram), David Malien Nminibapiel

Electrical & Computer Engineering Theses & Dissertations

Current state-of-the-art memory technologies such as FLASH, Static Random Access Memory (SRAM) and Dynamic RAM (DRAM) are based on charge storage. The semiconductor industry has relied on cell miniaturization to increase the performance and density of memory technology, while simultaneously decreasing the cost per bit. However, this approach is not sustainable because the charge-storage mechanism is reaching a fundamental scaling limit. Although stack engineering and 3D integration solutions can delay this limit, alternate strategies based on non-charge storage mechanisms for memory have been introduced and are being actively pursued.

Resistive Random Access Memory (RRAM) has emerged as one of the …

Ultrafast Electron Diffraction Study Of The Dynamics Of Antimony Thin Films And Nanoparticles, Mahmoud Abdel-Fattah

Electrical & Computer Engineering Theses & Dissertations

The ultrafast fast phenomena that take place following the application of a 120 fs laser pulse on 20 nm antimony thin films and 40 nm nanoparticles were studied using time-resolved electron diffraction. Samples are prepared by thermal evaporation, at small thickness (< 10 nm) antimony nanoparticles form while at larger thicknesses we get continuous thin films.

The samples are annealed and studied by static heating to determine their Debye temperatures, which were considerably less than the standard value. The thermal expansion under static heating also yielded the expansion coefficient of the sample material. Nanoparticle samples gave a very accurate thermal expansion coefficient (11 × 10^-6 K^-1).

Ultrafast time resolved electron diffraction …

Synthesis Of Ald Zinc Oxide And Thin Film Materials Optimization For Uv Photodetector Applications, Kandabara Nouhoum Tapily

Electrical & Computer Engineering Theses & Dissertations

Zinc oxide (ZnO) is a direct, wide bandgap semiconductor material. It is thermodynamically stable in the wurtzite structure at ambient temperature conditions. ZnO has very interesting optical and electrical properties and is a suitable candidate for numerous optoelectronic applications such as solar cells, LEDs and UV-photodetectors. ZnO is a naturally n-type semiconductor. Due to the lack of reproducible p-type ZnO, achieving good homojunction ZnO-based photodiodes such as UV-photodetectors remains a challenge. Meanwhile, heterojunction structures of ZnO with p-type substrates such as SiC, GaN, NiO, AlGaN, Si etc. are used; however, those heterojunction diodes suffer from low efficiencies. ZnO is an …

A Systematic Study Of Atomic Layer Deposition Of Platinum Nano-Scale Metallization Films And Their Application To Electrical Contacts In Porous Alumina Templates, Ngoc H. Tran

Electrical & Computer Engineering Theses & Dissertations

ln this thesis a comprehensive analysis is presented on nano-scale thin films of platinum deposited with Angstrom resolution by Atomic Layer Deposition (ALD) technology utilizing the Cambridge Nanotech Savannah 100 ALD system. Physical characterizations of film thickness, film morphology, and surface roughness of the deposited platinum were all performed before and after rapid thermal annealing (RTA) and as a function of forming gas annealing (FGA). Noble metal thin films of platinum were deposited on four inch wafers of p-type boron doped &100& oriented silicon (Si) substrates. The ALD film thickness was measured with a novel method utilizing the linear dependence …

Surface Pre-Treatments And Fabrication Of Highly Ordered Anodic Aluminum Oxide Nanopores At Room Temperature, Sampath Chennuri

Electrical & Computer Engineering Theses & Dissertations

The object of this work is to develop a novel approach to fabricate model membranes of well-defined and well aligned nanostructured materials in a robust environment. The main focus is on electrochemical synthesis, involving anodic oxidation of high purity aluminum sheets to form porous oxide films. Alumina films were prepared by anodizing highly pure aluminum (99.999%) in acidic electrolytes. Anodization parameters (current density, temperature, applied voltage, anodization time and electrolyte concentration) were selected with respect to the electrolyte used.

The primary challenge in nanotechnology is the creation of nanometer-scaled objects with as narrow a size distribution as possible for a …

Simulation And Modeling Of Nerve Impulse Propagation And Its Blockage By External Electrical Stimulation, Nidhi Nahar

Electrical & Computer Engineering Theses & Dissertations

The electric nature of biological tissues permits the transmission of signals for information and for control and is, therefore, of vital importance for life. The latest scientific achievements and nanoscale probing techniques now allow scientists to research at the subcellular level by measuring the electric current flows through a single ion channel of the cell membrane with the patch-clamp method. With the latter approach, the effects of electrical stimulation can be quantified, understood, and applied to molecular biology and the development of medical diagnostic and therapeutic methods.

In this thesis, the Hodgkin-Huxley approach for unmyelinated fibers, coupled with a transmission …

Real-Time Measurements On The Effects Of Ultra-Short High Voltage Pulses On Hl-60 Cells, Michalis C. Artemiou

Electrical & Computer Engineering Theses & Dissertations

The application of high voltage microsecond pulses that are above a critical value, to biological cells, has been shown to cause electroporation (Neumann, 1989). In addition, ultra-short pulses of several tens to hundreds of nanoseconds duration have been recently shown to affect intracellular structures without disturbing the plasma membrane (Schoenbach, 2001). However, such ultra-short intense pulses are expected to cause deformation of cells due to Maxwell stresses. This deformation was studied by means of an imaging technique with 10 ns temporal resolution on HL-60 cells. The imaging system consists of an inverted microscope where a spark light source was used …

Modeling Nerve Electro-Stimulation In The Nanosecond Regime, Feng Chen

Electrical & Computer Engineering Theses & Dissertations

Numerical simulations of electrical stimulation of frog gastrocnemius muscles have been carried out for pulse durations in the nanosecond regime. There are a number of potential advantages in using ultra-short pulses for neural stimulation, and no previous electro-stimulation work in the sub-microsecond regime has been reported. A timedependent, three-dimensional analysis model was developed and implemented for three distinct situations: (i) direct stimulation via electrode contact, (ii) indirect excitation based on electrodes immersed in a saline-filled bath, and (iii) remote electromagnetic stimulation through vacuum. The simulations yielded strength-dm ation (S-D) curves with pulse durations as short as 5 ns. Good agreement …