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As the 3rd generation solar cell, quantum dot solar cells are expected to outperform the first 2 generations with higher efficiency and lower manufacture cost. Currently the main problems for QD cells are the low conversion efficiency and stability. This work is trying to improve the reliability as well as

As the 3rd generation solar cell, quantum dot solar cells are expected to outperform the first 2 generations with higher efficiency and lower manufacture cost. Currently the main problems for QD cells are the low conversion efficiency and stability. This work is trying to improve the reliability as well as the device performance by inserting an interlayer between the metal cathode and the active layer. Titanium oxide and a novel nitrogen doped titanium oxide were compared and TiOxNy capped device shown a superior performance and stability to TiOx capped one. A unique light anneal effect on the interfacial layer was discovered first time and proved to be the trigger of the enhancement of both device reliability and efficiency. The efficiency was improved by 300% and the device can retain 73.1% of the efficiency with TiOxNy when normal device completely failed after kept for long time. Photoluminescence indicted an increased charge disassociation rate at TiOxNy interface. External quantum efficiency measurement also inferred a significant performance enhancement in TiOxNy capped device, which resulted in a higher photocurrent. X-ray photoelectron spectrometry was performed to explain the impact of light doping on optical band gap. Atomic force microscopy illustrated the effect of light anneal on quantum dot polymer surface. The particle size is increased and the surface composition is changed after irradiation. The mechanism for performance improvement via a TiOx based interlayer was discussed based on a trap filling model. Then Tunneling AFM was performed to further confirm the reliability of interlayer capped organic photovoltaic devices. As a powerful tool based on SPM technique, tunneling AFM was able to explain the reason for low efficiency in non-capped inverted organic photovoltaic devices. The local injection properties as well as the correspondent topography were compared in organic solar cells with or without TiOx interlayer. The current-voltage characteristics were also tested at a single interested point. A severe short-circuit was discovered in non capped devices and a slight reverse bias leakage current was also revealed in TiOx capped device though tunneling AFM results. The failure reason for low stability in normal devices was also discussed comparing to capped devices.
ContributorsYu, Jialin (Author) / Jabbour, Ghassan E. (Thesis advisor) / Alford, Terry L. (Thesis advisor) / Yu, Hongbin (Committee member) / Arizona State University (Publisher)
Created2011
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Description
Semiconductor nanowires are featured by their unique one-dimensional structure which makes them promising for small scale electronic and photonic device applications. Among them, III-V material nanowires are particularly outstanding due to their good electronic properties. In bulk, these materials reveal electron mobility much higher than conventional silicon based devices, for

Semiconductor nanowires are featured by their unique one-dimensional structure which makes them promising for small scale electronic and photonic device applications. Among them, III-V material nanowires are particularly outstanding due to their good electronic properties. In bulk, these materials reveal electron mobility much higher than conventional silicon based devices, for example at room temperature, InAs field effect transistor (FET) has electron mobility of 40,000 cm2/Vs more than 10 times of Si FET. This makes such materials promising for high speed nanowire FETs. With small bandgap, such as 0.354 eV for InAs and 1.52 eV for GaAs, it does not need high voltage to turn on such devices which leads to low power consumption devices. Another feature of direct bandgap allows their applications of optoelectronic devices such as avalanche photodiodes. However, there are challenges to face up. Due to their large surface to volume ratio, nanowire devices typically are strongly affected by the surface states. Although nanowires can be grown into single crystal structure, people observe crystal defects along the wires which can significantly affect the performance of devices. In this work, FETs made of two types of III-V nanowire, GaAs and InAs, are demonstrated. These nanowires are grown by catalyst-free MOCVD growth method. Vertically nanowires are transferred onto patterned substrates for coordinate calibration. Then electrodes are defined by e-beam lithography followed by deposition of contact metals. Prior to metal deposition, however, the substrates are dipped in ammonium hydroxide solution to remove native oxide layer formed on nanowire surface. Current vs. source-drain voltage with different gate bias are measured at room temperature. GaAs nanowire FETs show photo response while InAs nanowire FETs do not show that. Surface passivation is performed on GaAs FETs by using ammonium surfide solution. The best results on current increase is observed with around 20-30 minutes chemical treatment time. Gate response measurements are performed at room temperature, from which field effect mobility as high as 1490 cm2/Vs is extracted for InAs FETs. One major contributor for this is stacking faults defect existing along nanowires. For InAs FETs, thermal excitations observed from temperature dependent results which leads us to investigate potential barriers.
ContributorsLiang, Hanshuang (Author) / Yu, Hongbin (Thesis advisor) / Ferry, David (Committee member) / Tracy, Clarence (Committee member) / Arizona State University (Publisher)
Created2011
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Description
A workload-aware low-power neuromorphic controller for dynamic power and thermal management in VLSI systems is presented. The neuromorphic controller predicts future workload and temperature values based on the past values and CPU performance counters and preemptively regulates supply voltage and frequency. System-level measurements from stateof-the-art commercial microprocessors are used to

A workload-aware low-power neuromorphic controller for dynamic power and thermal management in VLSI systems is presented. The neuromorphic controller predicts future workload and temperature values based on the past values and CPU performance counters and preemptively regulates supply voltage and frequency. System-level measurements from stateof-the-art commercial microprocessors are used to get workload, temperature and CPU performance counter values. The controller is designed and simulated using circuit-design and synthesis tools. At device-level, on-chip planar inductors suffer from low inductance occupying large chip area. On-chip inductors with integrated magnetic materials are designed, simulated and fabricated to explore performance-efficiency trade offs and explore potential applications such as resonant clocking and on-chip voltage regulation. A system level study is conducted to evaluate the effect of on-chip voltage regulator employing magnetic inductors as the output filter. It is concluded that neuromorphic power controller is beneficial for fine-grained per-core power management in conjunction with on-chip voltage regulators utilizing scaled magnetic inductors.
ContributorsSinha, Saurabh (Author) / Cao, Yu (Thesis advisor) / Bakkaloglu, Bertan (Committee member) / Yu, Hongbin (Committee member) / Christen, Jennifer B. (Committee member) / Arizona State University (Publisher)
Created2011
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Description

This thesis identifies and explains two main problems students face during their internships. The first problem relates to feeling bored at internships due to the simplicity of projects or lack of work. From the interviews conducted, several strategies to avoid this boredom were created, including having employers design education plans

This thesis identifies and explains two main problems students face during their internships. The first problem relates to feeling bored at internships due to the simplicity of projects or lack of work. From the interviews conducted, several strategies to avoid this boredom were created, including having employers design education plans for interns to further their knowledge in programs such as excel during their downtime. The second problem with internships discovered focuses on the gap between what is taught in schools versus what is expected of interns in practice. This thesis identifies several opportunities for improvement in education and strategies on how to handle feeling overwhelmed on intern projects due to lack of knowledge.

ContributorsKomarnyckyj, Katya (Author) / Byrne, Jared (Thesis director) / Crawford, Cassidy (Committee member) / School of Molecular Sciences (Contributor) / Department of Finance (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

When examining the average college campus, it becomes obvious that students feel rushed from one place to another as they try to participate in class, clubs, and extracurricular activities. One way that students can feel more comfortable and relaxed around campus is to introduce the aspect of gaming. Studies show

When examining the average college campus, it becomes obvious that students feel rushed from one place to another as they try to participate in class, clubs, and extracurricular activities. One way that students can feel more comfortable and relaxed around campus is to introduce the aspect of gaming. Studies show that “Moderate videogame play has been found to contribute to emotional stability” (Jones, 2014). This demonstrates that the stress of college can be mitigated by introducing the ability to interact with video games. This same concept has been applied in the workplace, where studies have shown that “Gaming principles such as challenges, competition, rewards and personalization keep employees engaged and learning” (Clark, 2020). This means that if we manage to gamify the college experience, students will be more engaged which will increase and stabilize the retention rate of colleges which utilize this type of experience. Gaming allows students to connect with their peers in a casual environment while also allowing them to find resources around campus and find new places to eat and relax. We plan to gamify the college experience by introducing augmented reality in the form of an app. Augmented reality is “. . . a technology that combines virtual information with the real world” (Chen, 2019). College students will be able to utilize the resources and amenities available to them on campus while completing quests that help them within the application. This demonstrates the ability for video games to engage students using artificial tasks but real actions and experiences which help them feel more connected to campus. Our Founders Lab team has developed and tested an AR application that can be used to connect students with their campus and the resources available to them.

ContributorsKlein, Jonathan (Co-author) / Rangarajan, Padmapriya (Co-author) / Li, Shimei (Co-author) / Byrne, Jared (Thesis director) / Pierce, John (Committee member) / School of International Letters and Cultures (Contributor) / Department of Management and Entrepreneurship (Contributor) / Sandra Day O'Connor College of Law (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

Waste pickers are the victims of harsh economic and social factors that have hurt many developing countries and billions of people around the world. Due to the rise of industrialization since the 19th century, waste and disposable resources have been discarded around the world to provide more resources, products, and

Waste pickers are the victims of harsh economic and social factors that have hurt many developing countries and billions of people around the world. Due to the rise of industrialization since the 19th century, waste and disposable resources have been discarded around the world to provide more resources, products, and services to wealthy countries. This has put developing countries in a precarious position where people have had very few economic opportunities besides taking on the role of waste pickers, who not only face physical health consequences due to the work they do but also face exclusion from society due to the negative views of waste pickers. Many people view waste pickers as scavengers and people who survive off of doing dirty work, which creates tensions between waste pickers and others in society. This even leads to many countries outlawing waste picking and has led to the brutal treatment of waste pickers throughout the world and has even led to thousands of waste pickers being killed by anti-waste picker groups and law enforcement organizations in many countries. <br/> Waste pickers are often at the bottom of supply-chains as they take resources that have been used and discarded, and provide them to recyclers, waste management organizations, and others who are able to turn these resources into usable materials again. Waste pickers do not have many opportunities to rise above the situation they are in as waste picking has become the only option for many people who need to provide for themselves and their families. They are not compensated very well for the work they do, which also contributes to the situation where waste pickers are forced into a position of severe health risks, backlash from society and governments, not being able to seek better opportunities due to a lack of earning potential, and not being connected with end-users. Now is the time to create new business models that solve these large problems in our global society and create a sustainable way to ensure that waste pickers are treated properly around the world.

ContributorsKidd, Isabella Joy (Co-author) / Kapps, Jack (Co-author) / Urbina-Bernal, Alejandro (Thesis director) / Byrne, Jared (Committee member) / Marseille, Alicia (Committee member) / Jordan, Amanda (Committee member) / Dean, W.P. Carey School of Business (Contributor) / Morrison School of Agribusiness (Contributor) / Sanford School of Social and Family Dynamics (Contributor) / Department of Finance (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

Though about 75 percent of American waste is recyclable, only 30 percent of it is actually recycled and less than ten percent of plastics disposed of in the United States in 2015 were recycled. A statistic like this demonstrates the immense need to increase recycling rates in order to move

Though about 75 percent of American waste is recyclable, only 30 percent of it is actually recycled and less than ten percent of plastics disposed of in the United States in 2015 were recycled. A statistic like this demonstrates the immense need to increase recycling rates in order to move towards cultivating a circular economy and benefiting the environment. With Arizona State University’s (ASU) extensive population of on-campus students and faculty, our team was determined to create a solution that would increase recycling rates. After conducting initial market research, our team incentives or education. We conducted market research through student surveys to determine the level of knowledge of our target audience and barriers to entry for local recycling and composting resources. Further, we gained insight into the medium of recycling and sustainability programs they would be interested in participating in. Overall, the results of our surveys demonstrated that a majority of students were interested in participating in these programs, if they were not already involved, and most students on-campus already had access to these resources. Despite having access to these sustainable practices, we identified a knowledge gap between students and their information on how to properly execute sustainable practices such as composting and recycling. In order to address this audience, our team created Circulearning, an educational program that aims to bridge the gap of knowledge and address immediate concerns regarding circular economy topics. By engaging audiences through our quick, accessible educational modules and teaching them about circular practices, we aim to inspire everyone to implement these practices into their own lives. Though our team began the initiative with a focus on implementing these practices solely to ASU campus, we decided to expand our target audience to implement educational programs at all levels after discovering the interest and need for this resource in our community. Our team is extremely excited that our Circulearning educational modules have been shared with a broad audience including students at Mesa Skyline High School, ASU students, and additional connections outside of ASU. With Circulearning, we will educate and inspire people of all ages to live more sustainably and better the environment in which we live.

ContributorsTam, Monet (Co-author) / Chakravarti, Renuka (Co-author) / Carr-Taylor, Kathleen (Co-author) / Byrne, Jared (Thesis director) / Marseille, Alicia (Committee member) / Jordan, Amanda (Committee member) / Department of Supply Chain Management (Contributor) / Department of Information Systems (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

This thesis looks at three different inventory management strategies that can be implemented into a small business. Using GameSet Style as a research subject, this study analyzes current practices and problems that can be fixed when dealing with an excess amount of inventory. The three inventory management strategies that are

This thesis looks at three different inventory management strategies that can be implemented into a small business. Using GameSet Style as a research subject, this study analyzes current practices and problems that can be fixed when dealing with an excess amount of inventory. The three inventory management strategies that are compared are demand forecasting, inventory management software, and ABC analysis. Inventory can be a small business's highest cost if not managed effectively. The goal for this thesis is to find the best obtainable solution for a small business like GameSet that can be implemented into their business strategy.

ContributorsPatterson, Alexandra Mercedes (Author) / Byrne, Jared (Thesis director) / Kahley, Lisa (Committee member) / Dean, W.P. Carey School of Business (Contributor) / Department of Finance (Contributor) / Department of Supply Chain Management (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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In this paper, our Founders Lab team members — Jacob Benevento, Sydney Evans, and Alec Whiteley — recount the year-long entrepreneurial journey that led to the creation and launch of our venture, Certified Circular. Certified Circular is a program that certifies on-campus events for implementing circular practices into their activities

In this paper, our Founders Lab team members — Jacob Benevento, Sydney Evans, and Alec Whiteley — recount the year-long entrepreneurial journey that led to the creation and launch of our venture, Certified Circular. Certified Circular is a program that certifies on-campus events for implementing circular practices into their activities as well as off-campus businesses. The venture was formed in response to our group’s propelling question and industry selection, which called on us to create and market a venture within the ethical circular economy.

ContributorsBenevento, Jacob Keith (Co-author) / Evans, Sydney (Co-author) / Whiteley, Alexander (Co-author) / Byrne, Jared (Thesis director) / Marseille, Alicia (Committee member) / Jordan, Amanda (Committee member) / Department of Marketing (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

This project is focused on exploring the features and benefits of self-cleaning seats. The Founder's Lab team conducted research to determine the proper markets for this technology.

ContributorsYang, Tiger (Author) / Byrne, Jared (Thesis director) / Nimmagadda, Viraj (Committee member) / Jawahar, Nandita (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05