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- Creators: Barrett, The Honors College
- Creators: Beethoven, Ludwig van, 1770-1827
Description
ABSTRACT This work seeks to develop a practical solution for short range ultrasonic communications and produce an integrated array of acoustic transmitters on a flexible substrate. This is done using flexible thin film transistor (TFT) and micro electromechanical systems (MEMS). The goal is to develop a flexible system capable of communicating in the ultrasonic frequency range at a distance of 10 - 100 meters. This requires a great deal of innovation on the part of the FDC team developing the TFT driving circuitry and the MEMS team adapting the technology for fabrication on a flexible substrate. The technologies required for this research are independently developed. The TFT development is driven primarily by research into flexible displays. The MEMS development is driving by research in biosensors and micro actuators. This project involves the integration of TFT flexible circuit capabilities with MEMS micro actuators in the novel area of flexible acoustic transmitter arrays. This thesis focuses on the design, testing and analysis of the circuit components required for this project.
ContributorsDaugherty, Robin (Author) / Allee, David R. (Thesis advisor) / Chae, Junseok (Thesis advisor) / Aberle, James T (Committee member) / Vasileska, Dragica (Committee member) / Arizona State University (Publisher)
Created2012
Description
Thin film transistors (TFTs) are being used in a wide variety of applications such as image sensors, radiation detectors, as well as for use in liquid crystal displays. However, there is a conspicuous absence of interface electronics for bridging the gap between the flexible sensors and digitized displays. Hence is the need to build the same. In this thesis, the feasibility of building mixed analog circuits in TFTs are explored and demonstrated. A flexible CMOS op-amp is demonstrated using a-Si:H and pentacene TFTs. The achieved performance is ¡Ö 50 dB of DC open loop gain with unity gain frequency (UGF) of 7 kHz. The op-amp is built on the popular 2 stage topology with the 2nd stage being cascoded to provide sufficient gain. A novel biasing circuit was successfully developed modifying the gm biasing circuit to retard the performance degradation as the TFTs aged. A switched capacitor 7 bit DAC was developed in only nMOS topology using a-Si:H TFTs, based on charge sharing concept. The DAC achieved a maximum differential non-linearity (DNL) of 0.6 least significant bit (LSB), while the maximum integral non-linearity (INL) was 1 LSB. TFTs were used as switches in this architecture; as a result the performance was quite unchanged even as the TFTs degraded. A 5 bit fully flash ADC was also designed using all nMOS a-Si:H TFTs. Gray coding was implemented at the output to avoid errors due to comparator meta-stability. Finally a 5 bit current steering DAC was also built using all nMOS a-Si:H TFTs. However, due to process variation, the DNL was increased to 1.2 while the INL was about 1.8 LSB. Measurements were made on the external stress effects on zinc indium oxide (ZIO) TFTs. Electrically induced stresses were studied applying DC bias on the gate and drain. These stresses shifted the device characteristics like threshold voltage and mobility. The TFTs were then mechanically stressed by stretching them across cylindrical structures of various radii. Both the subthreshold swing and mobility underwent significant changes when the stress was tensile while the change was minor under compressive stress, applied parallel to channel length.
ContributorsDey, Aritra (Author) / Allee, David R. (Thesis advisor) / Bakkaloglu, Bertan (Committee member) / Garrity, Douglas A (Committee member) / Song, Hongjiang (Committee member) / Clark, Lawrence T (Committee member) / Arizona State University (Publisher)
Created2011
Description
A low temperature amorphous oxide thin film transistor (TFT) backplane technology for flexible organic light emitting diode (OLED) displays has been developed to create 4.1-in. diagonal backplanes. The critical steps in the evolution of the backplane process include the qualification and optimization of the low temperature (200 °C) metal oxide process, the stability of the devices under forward and reverse bias stress, the transfer of the process to flexible plastic substrates, and the fabrication of white organic light emitting diode (OLED) displays. Mixed oxide semiconductor thin film transistors (TFTs) on flexible plastic substrates typically suffer from performance and stability issues related to the maximum processing temperature limitation of the polymer. A novel device architecture based upon a dual active layer enables significant improvements in both the performance and stability. Devices are directly fabricated below 200 ºC on a polyethylene naphthalate (PEN) substrate using mixed metal oxides of either zinc indium oxide (ZIO) or indium gallium zinc oxide (IGZO) as the active semiconductor. The dual active layer architecture allows for adjustment in the saturation mobility and threshold voltage stability without the requirement of high temperature annealing, which is not compatible with flexible colorless plastic substrates like PEN. The device performance and stability is strongly dependent upon the composition of the mixed metal oxide; this dependency provides a simple route to improving the threshold voltage stability and drive performance. By switching from a single to a dual active layer, the saturation mobility increases from 1.2 cm2/V-s to 18.0 cm2/V-s, while the rate of the threshold voltage shift decreases by an order of magnitude. This approach could assist in enabling the production of devices on flexible substrates using amorphous oxide semiconductors.
ContributorsMarrs, Michael (Author) / Raupp, Gregory B (Thesis advisor) / Vogt, Bryan D (Thesis advisor) / Allee, David R. (Committee member) / Arizona State University (Publisher)
Created2011
Description
The field of flexible displays and electronics gained a big momentum within the recent years due to their ruggedness, thinness, and flexibility as well as low cost large area manufacturability. Amorphous silicon has been the dominant material used in the thin film transistor industry which could only utilize it as N type thin film transistors (TFT). Amorphous silicon is an unstable material for low temperature manufacturing process and having only one kind of transistor means high power consumption for circuit operations. This thesis covers the three major researches done on flexible TFTs and flexible electronic circuits. First the characterization of both amorphous silicon TFTs and newly emerging mixed oxide TFTs were performed and the stability of these two materials is compared. During the research, both TFTs were stress tested under various biasing conditions and the threshold voltage was extracted to observe the shift in the threshold which shows the degradation of the material. Secondly, the design of the first flexible CMOS TFTs and CMOS gates were covered. The circuits were built using both inorganic and organic components (for nMOS and pMOS transistors respectively) and functionality tests were performed on basic gates like inverter, NAND and NOR gates and the working results are documented. Thirdly, a novel large area sensor structure is demonstrated under the Electronic Textile project section. This project is based on the concept that all the flexible electronics are flexible in only one direction and can not be used for conforming irregular shaped objects or create an electronic cloth for various applications like display or sensing. A laser detector sensor array is designed for proof of concept and is laid in strips that can be cut after manufacturing and weaved to each other to create a real flexible electronic textile. The circuit designed uses a unique architecture that pushes the data in a single line and reads the data from the same line and compares the signal to the original state to determine a sensor excitation. This architecture enables 2 dimensional addressing through an external controller while eliminating the need for 2 dimensional active matrix style electrical connections between the fibers.
ContributorsKaftanoglu, Korhan (Author) / Allee, David R. (Thesis advisor) / Kozicki, Michael N (Committee member) / Holbert, Keith E. (Committee member) / Kaminski, Jann P (Committee member) / Arizona State University (Publisher)
Created2012
Description
Circuits on smaller technology nodes become more vulnerable to radiation-induced upset. Since this is a major problem for electronic circuits used in space applications, designers have a variety of solutions in hand. Radiation hardening by design (RHBD) is an approach, where electronic components are designed to work properly in certain radiation environments without the use of special fabrication processes. This work focuses on the cache design for a high performance microprocessor. The design tries to mitigate radiation effects like SEE, on a commercial foundry 45 nm SOI process. The design has been ported from a previously done cache design at the 90 nm process node. The cache design is a 16 KB, 4 way set associative, write-through design that uses a no-write allocate policy. The cache has been tested to write and read at above 2 GHz at VDD = 0.9 V. Interleaved layout, parity protection, dual redundancy, and checking circuits are used in the design to achieve radiation hardness. High speed is accomplished through the use of dynamic circuits and short wiring routes wherever possible. Gated clocks and optimized wire connections are used to reduce power. Structured methodology is used to build up the entire cache.
ContributorsXavier, Jerin (Author) / Clark, Lawrence T (Thesis advisor) / Cao, Yu (Committee member) / Allee, David R. (Committee member) / Arizona State University (Publisher)
Created2012
Description
Geology and its tangential studies, collectively known and referred to in this thesis as geosciences, have been paramount to the transformation and advancement of society, fundamentally changing the way we view, interact and live with the surrounding natural and built environment. It is important to recognize the value and importance of this interdisciplinary scientific field while reconciling its ties to imperial and colonizing extractive systems which have led to harmful and invasive endeavors. This intersection among geosciences, (environmental) justice studies, and decolonization is intended to promote inclusive pedagogical models through just and equitable methodologies and frameworks as to prevent further injustices and promote recognition and healing of old wounds. By utilizing decolonial frameworks and highlighting the voices of peoples from colonized and exploited landscapes, this annotated syllabus tackles the issues previously described while proposing solutions involving place-based education and the recentering of land within geoscience pedagogical models. (abstract)
ContributorsReed, Cameron E (Author) / Richter, Jennifer (Thesis director) / Semken, Steven (Committee member) / School of Earth and Space Exploration (Contributor, Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
The ASU COVID-19 testing lab process was developed to operate as the primary testing site for all ASU staff, students, and specified external individuals. Tests are collected at various collection sites, including a walk-in site at the SDFC and various drive-up sites on campus; analysis is conducted on ASU campus and results are distributed virtually to all patients via the Health Services patient portal. The following is a literature review on past implementations of various process improvement techniques and how they can be applied to the ABCTL testing process to achieve laboratory goals. (abstract)
ContributorsKrell, Abby Elizabeth (Co-author) / Bruner, Ashley (Co-author) / Ramesh, Frankincense (Co-author) / Lewis, Gabriel (Co-author) / Barwey, Ishna (Co-author) / Myers, Jack (Co-author) / Hymer, William (Co-author) / Reagan, Sage (Co-author) / Compton, Carolyn (Thesis director) / McCarville, Daniel R. (Committee member) / Industrial, Systems & Operations Engineering Prgm (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
The students of Arizona State University, under the mentorship of Dr George Karady, have been collaborating with Salt River Project (SRP), a major power utility in the state of Arizona, trying to study and optimize a battery-supported grid-tied rooftop Photovoltaic (PV) system, sold by a commercial vendor. SRP believes this system has the potential to satisfy the needs of its customers, who opt for utilizing solar power to partially satisfy their power needs.
An important part of this elaborate project is the development of a new load forecasting algorithm and a better control strategy for the optimized utilization of the storage system. The built-in algorithm of this commercial unit uses simple forecasting and battery control strategies. With the recent improvement in Machine Learning (ML) techniques, development of a more sophisticated model of the problem in hand was possible. This research is aimed at achieving the goal by utilizing the appropriate ML techniques to better model the problem, which will essentially result in a better solution. In this research, a set of six unique features are used to model the load forecasting problem and different ML algorithms are simulated on the developed model. A similar approach is taken to solve the PV prediction problem. Finally, a very effective battery control strategy is built (utilizing the results of the load and PV forecasting), with the aim of ensuring a reduction in the amount of energy consumed from the grid during the “on-peak” hours. Apart from the reduction in the energy consumption, this battery control algorithm decelerates the “cycling aging” or the aging of the battery owing to the charge/dis-charges cycles endured by selectively charging/dis-charging the battery based on need.
ii
The results of this proposed strategy are verified using a hardware implementation (the PV system was coupled with a custom-built load bank and this setup was used to simulate a house). The results pertaining to the performances of the built-in algorithm and the ML algorithm are compared and the economic analysis is performed. The findings of this research have in the process of being published in a reputed journal.
An important part of this elaborate project is the development of a new load forecasting algorithm and a better control strategy for the optimized utilization of the storage system. The built-in algorithm of this commercial unit uses simple forecasting and battery control strategies. With the recent improvement in Machine Learning (ML) techniques, development of a more sophisticated model of the problem in hand was possible. This research is aimed at achieving the goal by utilizing the appropriate ML techniques to better model the problem, which will essentially result in a better solution. In this research, a set of six unique features are used to model the load forecasting problem and different ML algorithms are simulated on the developed model. A similar approach is taken to solve the PV prediction problem. Finally, a very effective battery control strategy is built (utilizing the results of the load and PV forecasting), with the aim of ensuring a reduction in the amount of energy consumed from the grid during the “on-peak” hours. Apart from the reduction in the energy consumption, this battery control algorithm decelerates the “cycling aging” or the aging of the battery owing to the charge/dis-charges cycles endured by selectively charging/dis-charging the battery based on need.
ii
The results of this proposed strategy are verified using a hardware implementation (the PV system was coupled with a custom-built load bank and this setup was used to simulate a house). The results pertaining to the performances of the built-in algorithm and the ML algorithm are compared and the economic analysis is performed. The findings of this research have in the process of being published in a reputed journal.
ContributorsHariharan, Aashiek (Author) / Karady, George G. (Thesis advisor) / Heydt, Gerald Thomas (Committee member) / Qin, Jiangchao (Committee member) / Allee, David R. (Committee member) / Arizona State University (Publisher)
Created2018
Description
For as long as humans have been working, they have been looking for ways to get that work done better, faster, and more efficient. Over the course of human history, mankind has created innumerable spectacular inventions, all with the goal of making the economy and daily life more efficient. Today, innovations and technological advancements are happening at a pace like never seen before, and technology like automation and artificial intelligence are poised to once again fundamentally alter the way people live and work in society. Whether society is prepared or not, robots are coming to replace human labor, and they are coming fast. In many areas artificial intelligence has disrupted entire industries of the economy. As people continue to make advancements in artificial intelligence, more industries will be disturbed, more jobs will be lost, and entirely new industries and professions will be created in their wake. The future of the economy and society will be determined by how humans adapt to the rapid innovations that are taking place every single day. In this paper I will examine the extent to which automation will take the place of human labor in the future, project the potential effect of automation to future unemployment, and what individuals and society will need to do to adapt to keep pace with rapidly advancing technology. I will also look at the history of automation in the economy. For centuries humans have been advancing technology to make their everyday work more productive and efficient, and for centuries this has forced humans to adapt to the modern technology through things like training and education. The thesis will additionally examine the ways in which the U.S. education system will have to adapt to meet the demands of the advancing economy, and how job retraining programs must be modernized to prepare workers for the changing economy.
ContributorsCunningham, Reed P. (Author) / DeSerpa, Allan (Thesis director) / Haglin, Brett (Committee member) / School of International Letters and Cultures (Contributor) / Department of Finance (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Businesses stand to face many uncertainties from the moment they start up to every moment in between. A business can try to recognize them and plan ahead, react to them as they occur, or be rocked by a black swan they never saw coming. How a business deals with unforeseen events can increase its potential for success or failure. With this in mind, there is no better bridge between the here and now and the future than planning for change in order to move a company toward preparing for change, adapting to change and achieving optimal results. Interested in taking a step toward the digital age, Alpha Homes Management, Inc. (Alpha Homes) sought our help to explore ideas and options to take their company to a new level. This Barrett Creative Project was centered on designing a system for Alpha Homes that will replace their outdated paper-based system with a more digital one. This aligns with the project also featured as a capstone project as required by the information technology degree expectations. In supplement to the capstone, and for the Barrett Creative Project, the final product was presented to the owners of Alpha Homes Management, Inc. to be utilized by the business. The end goal is to provide a platform which provides a paperless environment for documentation and bring the company a step closer to having a robust internet presence. Now that the web-based application product has been created and presented, the testing phase can now begin to evaluate its efficacy.
ContributorsBrice-Nash, Tristan (Co-author) / Alfawzan, Mohammad (Co-author) / Doheny, Damien (Thesis director) / Rodriguez, Carlos (Committee member) / Information Technology (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05