A method of locating electric transmission line towers using
ground survey data in a digital computer program is presented in this
thesis. The towers are located for maximum spacing subject to the
constraints of available tower heights, forbidden ground areas, minimum
ground clearance, and specified conductor tensions. The digital
method...
This thesis proposes a criteria for the evaluation of those variable
parameters that influence the response of a hydroelectric generator
driven by a hydraulic turbine of the Kaplan type. It is considered
a requirement that a unit must be stable when supplying an isolated
load and it is assumed that...
The comparative values of impedance and resistance to reactance
ratios are important parameters in determining the load
capacity of an interconnection of power transformer, called a bank.
The full design capabilities of parallel or three-phase connected
transformers cannot be utilized unless the following constraints are
applied.
1. All transformer voltage...
This simulation is a model for a tidal power-peaking plant that
can be used to determine the electrical peaking generation for a given
set of conditions.
The simulation internally contains a tide producing function
for a specific year, the hydraulic characteristics of the plant, and the
plant's machines' characteristics. The...
Measurements
were
made
of the
energy
loss
in
a
superconducting
wire
coil
subjected
to
an
axial
magnetic
field
consisting
of
a
ripple
field
superimposed
on
a
steady
field.
The
loss
was
measured
calorimetrically
using
a
sonic
thermometer
consisting
of
a
resonance tube
filled
with
helium
gas
in
thermal
contact
with...
The three-phase squirrel-cage induction motor is rugged, compact,
inexpensive, can be totally enclosed and requires little maintenance.
Its use as a variable speed drive has been limited, however, by the
state-of-the art of control components.
The advent and continuing development of the silicon controlled
rectifier and associated solid-state components has...
A method is presented for developing a detailed non-linear
voltage regulator system model representation for use in power
system stability studies. This model is implemented within MIMIC,
a digital simulator program, with a particular set of data which
could be taken from field tests. Results are presented from simulations
of...
An instruction set and programming examples are described for
a Distributed Logic Memory computer organization. The computer is
designed to take advantage of the economies of very large-scale circuit
integration. In addition, the computer can grow in an orderly
way. As it grows there is increased parallelism possible so that...
The present thesis is about the electric power distribution system
for the city of Mecca, in Saudi Arabia. The distribution system
of Mecca started suddenly, grew haphazardly and developed quickly
with a load factor as high as 38%. Lack of planning, records and
training plus insufficient experience of management evolved...
The integration of the southern electrical system with the
balance of Thailand has many desirable features, but technical and
economic problems make this a difficult task. It is over 300 miles
between the nearest practical points of the interconnection. In the
next ten years, there will probably be a maximum...
This thesis develops a simulation model for a cumulative connected
compound direct-current generator to varify the operation of
this machine under conditions of slowly and rapidly changing loads.
The application of this simulation method will contribute to
more exact modeling of power system components. The accuracy
gained is in the...
The North American interconnected power systems continuously
attempt to hold power system time as close to standard time as possible.
All inherent problems associated with normal power system
operation make this a difficult task. System time is presently allowed
to deviate from standard time by up to two seconds before...
The purpose of this thesis is to investigate the necessity of
transposition in the construction of overhead transmission lines.
Line currents, line voltages and line losses of both the transposed
and untransposed lines were calculated and compared for two different
voltage classes. The conventional method of symmetrical components
was used...
In this thesis, a digital computer method for locating transmission
line towers is presented. The computer program selects the
position of both angle and tangent type towers for a given ground profile.
This selection will provide a minimum cost per foot of
transmission line in terms of the average costs...
An algorithm for computing the parameter sensitivities of an excitation system for a hydroelectric generation system is developed for model analysis in this thesis. The IEEE Type 1 excitation system representation, linked with a simplified alternator and voltage regulator equivalent, provide a closed-loop model for digital simulation. Parametric sensitivities are...
This thesis develops a simplified and logical simulation model
for an amplidyne excitation system for a synchronous generator with
an automatic voltage regulator.
The non-transfer function representation using field determined
parameters including variable inductance and machine saturation
was used to reduce the computing time for the stability analysis.
The simulation...
This fault detection scheme is based on sampling the instantaneous
phase voltages and checking their sum and magnitude against
a specified voltage. Faults on the system cause unbalances and
distortion of the phase voltages and currents. The currents and
voltages change in magnitude and/or phase position with respect to
the...
The scope of this project was to build a high
energy impulse generator to be used for educational
and research purposes, such as small scale modeling
of lightning and switching surges or small scale
simulation of an electromagnetic pulse (EMP).
A one-stage impulse generator was designed to
deliver a voltage...
The utilization of extra-high-voltage underground power cables
over distances greater than 100 miles presents serious problems relative
to the voltage and current limits of such cables. These problems
are directly associated with the fixed amount of capacitance inherent
in long cable lines. As a result, large charging currents are
characteristic...
The purpose of this thesis is to represent and calculate unsymmetrical
secondary faults on a grounded wye-to-delta transformer
bank.
This thesis is specifically concerned with the secondary connections
often encountered in industrial installations. Faults on these
systems have not been adequately investigated.
Three types of faults are considered, namely:
1....
Nucleation in atomic layer deposition (ALD) determines how many cycles are required to initiate growth and to form a continuous film. Nucleation has been exploited for the formation of nanoparticles, catalysts, and for area-selective ALD. Although sometimes overlooked or misrepresented in ALD reports, nucleation is also critical for multicomponent ALD...
Atomic layer deposition (ALD) is an enabling technique for many new micro- and nanoscale technologies. The self-limiting surface chemical reactions by which ALD fundamentally operates give rise to uniquely high precision (atomic) control over deposited film thickness, uniformity over large areas, and conformality over complex and extreme topographies. One such...
Metal-insulator-metal (MIM) and dual-insulator MIM (MIIM) devices are used in rectennas, hot-electron transistors, single electron transistors, resistive random access memory (RRAM), and capacitors. The performance of these devices relies heavily on the energy barrier height at each metal-insulator interface. Thus, determination of the in-situ electron energy barrier at each interface...
The research presented herein focuses on electrical assessment of oxide thin films as insulators. The current density-electric field (J-E) characteristics of four insulators of dramatically different electrical quality are assessed in terms of their operative electronic conduction mechanisms. Conduction in the two high-quality insulators is dominated by Ohmic conduction and...
In the first part of this work, thin films of Al₂O₃ deposited via atomic layer deposition (ALD) are demonstrated to improve the thermal stability of cellulose nanocrystal (CNC) aerogels. ALD is a chemical vapor deposition (CVD) like method in which sequential precursor exposures and self-limited surface reactions produce a conformal...
The trend towards higher resolution, faster refresh rate active-matrix liquid-crystal displays (AMLCDs) as well as the emergence of active-matrix organic light-emitting diode (AMOLED) displays is driving the demand for amorphous oxide semiconductor thin-film transistors (AOS TFTs) with higher mobility. A physics-based model for carrier transport in an amorphous semiconductor is...
The electrical stability of amorphous indium-gallium-zinc oxide (a-IGZO) thinfilmtransistors (TFTs) is investigated for flat-panel display applications. Althoughproducts incorporating a-IGZO TFT backplanes are already commercially available,e.g., iMac with 5K retina display, technical challenges need to be addressed for nextgenerationapplications, e.g., active-matrix organic light-emitting diode displays.Device stability is one crucial issue. The...
CIGS and CdTe based commercial thin-film solar cells (TFSCs) require an absorber thickness greater than 2 µm and 4 µm, respectively, to adequately absorb the solar spectrum. To efficiently extract photoexcited electrons, these TFSCs require relatively defect-free absorbers with high-minority carrier mobility (> 100 cm2V−1s−1) and long lifetime (> 10...
Back end of line (BEOL) metal-insulator-metal capacitors (MIMCAPs) have become a core passive component in modern integrated circuits. International Technology Roadmap for Semiconductors (ITRS) projections for scaling of analog/mixed-signal MIMCAP applications require simultaneously increasing capacitance density while maintaining low leakage current density and low voltage nonlinearity (characterized by the quadratic...
Due to a lack of grain boundaries, an amorphous metal thin film (AMTF) possesses advantageous mechanical properties and enhanced chemical stability that is potentially useful for thermal inkjet (TIJ) printing applications. The use of an AMTF as a TIJ resistor or cavitation plate could lead to a thinner TIJ cavitation...
Transparent conductive oxides (TCOs), primarily indium doped tin oxide, have been widely used in numerous fields since decades ago, such as solar cells, displays, OLEDs and ‘smart windows’ etc. Owing to the scarcity of indium, there is a great demand for new alternative materials. Metal/insulator/metal (MIM) diodes are a critical...
As scaling of silicon (Si) based devices approaches fundamental limits, thin film metal-insulator-metal (MIM) tunnel diodes are attracting interest due to their potential for high speed operation. Because operation of these devices is based on tunneling, electrode / interfacial roughness is critical. Recently, it was shown that combining ultra-smooth bottom...
Diabetes is a pandemic that affects nearly 29.1 million Americans and the fourth leading cause of mortality in the US. Type 1 diabetes is a chronic condition which occurs due to little to no production of insulin by the pancreas. This form of diabetes requires constant monitoring of blood glucose...
The objective of the work reported herein is to explore the impact of decreasing channel thickness on radio-frequency (RF) sputtered amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) electrical performance through the evaluation of drain current versus gate voltage (I[subscript D] − V[subscript G]) transfer curves. For a fixed set of...
The aim of the research undertaken for this thesis was to develop a new high-performance amorphous oxide semiconductor (AOS) for use as a channel layer in a thin-film transistor (TFT). AOS TFTs offer higher electron mobility than the established amorphous silicon based technology. A new channel material comprised of aluminum...
The research presented herein represents an effort to combine the ultra-smooth surface of an amorphous metal thin film (AMTF) with a solution-processed dielectric synthesized via prompt inorganic condensation (PIC). Analysis of dielectric film quality is carried out via electrical measurements of metal-insulator-metal (MIM) diodes. Anneals at 500 and 700 °C...
Current cadmium telluride and copper indium gallium diselenide thin-film solar cells
(TFSCs) utilize thick absorbers (2 - 4 μm). For efficient carrier extraction in these TFSCs,
the absorber layer requires high carrier mobilities and a long minority carrier lifetime, which
necessitates the use of a high purity, defect-free thin film....
Amorphous metal thin films (AMTFs) are of potential use for metal-insulator-metal (MIM) tunnel diode applications due to their ultra-smooth surfaces, a consequence of their amorphous microstructure. The objective of this thesis is to design a thermally-stable AMTF capable of maintaining MIM tunnel diode performance after a post-deposition anneal in excess...
Flexible electronics processing techniques were applied to integrate a glucose sensor with a hormone-delivery catheter in order to create a cheap and minimally invasive method for patients with type 1 diabetes to continually monitor and control their blood sugar levels. Ultimately, this work intends to move toward the development of...
White electroluminescence (EL) was observed for the
first time from diamond-like carbon (DLC) films at room
temperature. Electroluminescence was observed by the
application of ac voltages in excess of 200 V to a metal-insulator-
semiconductor (i.e. DLC)-insulator-metal (MISIM)
device structure.
For EL applications, three types of the DLC films were...
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....
The atomic solid state energy (SSE) scale is introduced as a tool for inorganic materials design. The SSE scale is obtained by assessing an average electron affinity (EA) (for a cation) or an average ionization potential (IP) (for an anion) for each atom using data from compounds having that specific...
The memristor is a resistive switching random access memory (RRAM) with a basic metal/insulator/metal (MIM) structure. These nano devices are nonvolatile, have a conceptually simple crossbar device structure, are power efficient and have the capability of switching between high and low resistance states in nanoseconds making them promising to replace...
The drain current of InP MISPETs is often observed
to decrease as a function of time after the application of
a positive gate bias which involves an accumulation of
electrons in the channel. Various models have been
proposed for this drain current drift (DCD) phenomenon.
In this thesis, variable-temperature bias-stress...
An analytical expression is derived which allows the
bulk minority carrier recombination lifetime, t, and the
surface recombination velocity, S, to be extracted from a
single noncontact photoconductivity decay (PCD) measurement. This analytical expression is rather complex, but
can be reduced to a first order approximation. The first
order approximation...
The stability of ZnS:Mn AC thin film Electroluminescence (ACEFEL)
devices as demonstrated by the brightness-voltage (BV)
characteristics is discussed. Two procedures for improvement of the
stability are demonstrated. The first method is the addition of a
CaS buffer layer to one or both interfaces of the ZnS active phosphor
layer....
A study of deep levels of the emitter region of a
heterojunction bipolar transistor is investigated using deep
level transient spectroscopy (DLTS), deep level admittance
spectroscopy (DLAS), thermally stimulated capacitance
(TSCAP), and capacitance-voltage (C-V) profiling. The DX
center, with an activation energy of 0.45 eV, is the only
deep level...
In this thesis the concept of inhomogeneous
dielectrics is demonstrated for various optical coating
applications. Compositionally-varying silicon oxynitride
(SiON) dielectric layers, with the refractive index
varying as a function of position, are grown by computer-controlled
plasma-enhanced chemical vapor deposition
(PECVD) using silane, nitrogen, and nitrous oxide reactant
gases. Compositionally graded...
Alternating-current thin-film electroluminescent (ACTFEL) devices are used in the
formation of pixels in flat panel displays. ACTFEL flat panel displays have many
advantages over other flat panel technologies. Specifically, ACTFEL panels are emissive
displays, they have high brightness, wide viewing angles, and rugged construction.
Although much is already known about...
Hot carrier effects in sub-micron lightly doped drain (LDD) n-channel
MOSFETs under static (DC) stress are studied in order to establish the degradation
mechanisms of such devices. Degradation is monitored as a function of time at various
gate voltages. Under accelerated aging conditions (i.e. large drain voltages) the gate
voltage...
The accomplishments presented in this thesis are the development of three models
for simulation of space charge generation in the phosphor layer of alternating current
thin-film electroluminescent (ACTFEL) devices and the results from simulation
of these models. First, a single sheet charge model is developed and simulated.
The single sheet...
The goal of this thesis is to identify and to explore novel ACTFEL phosphor
materials. Several important materials properties relevant to ACTFEL phosphor
development are identified. All of these properties cannot be obtained simultaneously.
Therefore, several key phosphor materials properties are identified as critical to the
development of an ACTFEL...
Fabrication techniques and process integration considerations for amorphous oxide semiconductor (AOS) thin-film transistors (TFTs) constitute the central theme of this dissertation. Within this theme three primary areas of focus are pursued.
The first focus involves formulating a general framework for assessing passivation. Avoiding formation of an undesirable backside accumulation layer...
An active-matrix electroluminescent (AMEL) design tool has been developed for
the simulation of AMEL display devices. The AMEL design tool is a software package
that simulates AMEL device operation using a lumped parameter circuit model. The
lumped parameter circuit model is developed primarily to address AMEL power
dissipation issues. The...
The goal of this thesis is the identification and synthesis of high-luminance,
primary color alternating-current thin-film electroluminescent (ACTFEL) devices.
Special attention is paid to the synthesis of primary color green ACTFEL devices because
of the lack of an adequate primary green ACTFEL phosphor and the dominance
of green wavelengths in...
In this thesis steady-state (i.e. steady-state with respect to the applied voltage waveform) transient current-transient voltage [i(t)-v(t)], transient brightness-transient current [b(t)-i(t)], transient brightness-transient voltage [b(t)-v(t)], transient current [i(t)], transient brightness [b(t)], and detrapped charge analysis are introduced as novel organic light emitting device (OLED) characterization methods. These analysis methods involve...
The main achievement of this thesis is the development of a two-sheet charge simulation model with space charge creation by trap-to-band impact ionization to describe the electrical characteristics of alternating-current thin-film electroluminescent (ACTFEL) devices. The two-sheet charge model localizes all of the space charge in the phosphor region of an...
The purpose of this thesis is to contribute to the understanding of SrS-based alternating-current thin-film electroluminescent (ACTFEL) device operation. Three main accomplishments serving this purpose are presented in this thesis. First, two new methods are developed for estimation of insulator capacitance in ACTFEL devices possessing a large amount of dynamic...
The achievements of this thesis are the development of several models for the SPICE (Simulation Program with Integrated Circuit Emphasis) simulation of alternating-current thin-film electroluminescent (ACTFEL) devices, organic light-emitting devices (OLEDs), and polymer light-emitting devices (PLEDs). First, an ACTFEL model based on the built-in HSPICE Fowler-Nordheim tunneling diode is developed,...
The goal of this thesis study is to develop an activated reactive evaporation (ARE) system and to demonstrate its utility by fabricating-alternating current thin-film electroluminescent (ACTFEL) oxide phosphor devices. ARE entails evaporation in an activated gas. The main ARE system components are three thermal evaporation sources, a microwave power supply,...
The objective of the research presented in this thesis is to develop, implement, and demonstrate the utility of an n-sheet, state-space alternating-current thin-film electroluminescent (ACTFEL) device model. In this model, the phosphor layer is discretized into n + 1 layers, with band-to-band impact ionization, space charge creation/ annihilation, and luminescent...
The objective of this thesis is to provide an initial demonstration of the feasibility of constructing highly transparent active electronic devices. Such a demonstration is successfully achieved in the fabrication of ZnO-based thin film transistors (TFTs) exhibiting transparency greater than ~90% in the visible portion of the electromagnetic spectrum and...
Current leading thin-film solar cell technologies, i.e., cadmium telluride (CdTe) and copper indium gallium diselenide (CIGS), employ elements which are either toxic (Cd), or rare and/or expensive (In, Te, Ga, and Cd). The aim of this thesis is to investigate new, abundant, non-toxic p-type semiconductors for potential solar absorber application....
This project examines the results of current-voltage conduction mechanism analysis techniques simulated under assumed conduction conditions. Thermionic emission and Fowler-Nordheim tunneling conditions are simulated and analyzed. The resulting plots show how devices behave under different condition mechanisms. The effects of different conduction mechanisms on the results of various analysis techniques...
Indium-gallium-zinc oxide (IGZO) and zinc-tin oxide (ZTO) are investigated for thin-film transistor (TFT) applications. Negative bias illumination stress (NBIS) is employed for electrical stability assessment. Unpassivated IGZO and ZTO TFTs suffer from severe NBIS instabilities. Zinc-tin-silicon oxide is found to be an effective passivation layer for IGZO and ZTO TFTs,...
The aim of this dissertation is to develop non-traditional approaches to alternating-current thin-film electroluminescent (ACTFEL) device fabrication. ACTFEL technology suffers from a lack of adequately bright and efficient primary-color phosphors and cannot presently compete in the low-cost display market. Therefore the research presented in this dissertation focuses on an exploration...
The focus of this thesis involves development of highly transparent, n-channel, accumulation- mode thin-film transistors employing a zinc tin oxide (ZTO) channel layer. ZTO-based transparent thin-film transistors (TTFTs) show improved device performance compared to ZnO-based TTFTs. An estimated peak effective mobility for these devices as high as ~100 cm² V⁻¹sec⁻¹...
The long-term goal of this research project is the development of solution-based inorganic dielectric and semiconductor materials for inkjet printed electronics. The main focus of this thesis involves testing of the materials and devices under development. A new solution-based inorganic dielectric material (HfOSO₄), given the name hafsox, is developed and...
Resistive random access memory (RRAM) is a non-volatile memory technology based on resistive switching in a dielectric or semiconductor sandwiched between two different metals. Also known as memristors, these devices are potential candidates for a next-generation replacement for flash memory. In this thesis, bipolar resistive switching is reported for the...
A class of high-performance thin-film transistor (TFT) channel materials has emerged
involving oxides composed of heavy-metal cations (HMCs) with (n-1)d¹⁰ns⁰ (n≥4)
electronic configurations. This thesis is devoted to the pursuit of three topics involving
the development of these materials for TFT applications: modeling TFT currentvoltage
characteristics, an exploratory method for...
The primary focus of this thesis involves modeling and development of p-type thin-film transistors (p-TFTs), moving towards the realization of a filly transparent thin-film transistor (TTFT). The modeling portion of this thesis emphasizes the development of physics-based TFT models, specifically focusing on the elucidation of non-ideal current-voltage characteristic behavior. A...
Atomic Layer Deposition (ALD) is a promising technique for the production of
biologically safe, wear resistant and corrosion protective coatings for orthopedic
applications. In this work, the impact of coating thickness and surface preparation on the
hardness (H), elastic modulus (E), wear resistance, and delamination of ALD Al2O3 films
is...
ZnO nanowires (NWs) are good candidates for chemical sensing because of their high surface-to-volume ratio. In this work, ZnO nanobridge sensors were fabricated utilizing a novel method which uses carbonized photoresist (C-PR) as a nucleation layer. The use of C-PR allows simultaneous growth and integration of NWs to lithographically-defined features....
The central focus of this thesis is the design, fabrication and characterization of amorphous oxide semiconductor (AOS) thin-film transistor (TFT) current mirrors. The thin-film deposition and circuit fabrication methods used to realize zinc tin oxide (ZTO) TFT
current mirrors are addressed in order to elucidate the processing challenges for this...
Nanolaminate dielectrics combine two or more insulating materials in a many-layered film. These structures can be made to significantly outperform films composed of a single one of their constituent materials by adjusting the composition ratio, arrangement, and size of the component layers. In this work, atomic layer deposition (ALD) is...
Thin films are an enabling technology for a wide range of applications, from microprocessors to diffusion barriers. Nanolaminate thin films combine two (or more) materials in a layered structure to achieve performance that neither film could provide on its own. Atomic layer deposition (ALD) is a chemical vapor deposition technique...