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- Member of: ASU Electronic Theses and Dissertations
Description
HgCdTe is the dominant material currently in use for infrared (IR) focal-plane-array (FPA) technology. In this dissertation, transmission electron microscopy (TEM) was used for the characterization of epitaxial HgCdTe epilayers and HgCdTe-based devices. The microstructure of CdTe surface passivation layers deposited either by hot-wall epitaxy (HWE) or molecular beam epitaxy (MBE) on HgCdTe heterostructures was evaluated. The as-deposited CdTe passivation layers were polycrystalline and columnar. The CdTe grains were larger and more irregular when deposited by HWE, whereas those deposited by MBE were generally well-textured with mostly vertical grain boundaries. Observations and measurements using several TEM techniques showed that the CdTe/HgCdTe interface became considerably more abrupt after annealing, and the crystallinity of the CdTe layer was also improved. The microstructure and compositional profiles of CdTe(211)B/ZnTe/Si(211) heterostructures grown by MBE was investigated. Many inclined {111}-type stacking faults were present throughout the thin ZnTe layer, terminating near the point of initiation of CdTe growth. A rotation angle of about 3.5° was observed between lattice planes of the Si substrate and the final CdTe epilayer. Lattice parameter measurement and elemental profiles indicated that some local intermixing of Zn and Cd had taken place. The average widths of the ZnTe layer and the (Cd, Zn)Te transition region were found to be roughly 6.5 nm and 3.5 nm, respectively. Initial observations of CdTe(211)B/GaAs(211) heterostructures indicated much reduced defect densities near the vicinity of the substrate and within the CdTe epilayers. HgCdTe epilayers grown on CdTe(211)B/GaAs(211) composite substrate were generally of high quality, despite the presence of precipitates at the HgCdTe/CdTe interface. The microstructure of HgCdSe thin films grown by MBE on ZnTe/Si(112) and GaSb(112) substrates were investigated. The quality of the HgCdSe growth was dependent on the growth temperature and materials flux, independent of the substrate. The materials grown at 100°C were generally of high quality, while those grown at 140°C had {111}-type stacking defects and high dislocation densities. For epitaxial growth of HgCdSe on GaSb substrates, better preparation of the GaSb buffer layer will be essential in order to ensure that high-quality HgCdSe can be grown.
ContributorsZhao, Wenfeng (Author) / Smith, David J. (Thesis advisor) / McCartney, Martha (Committee member) / Carpenter, Ray (Committee member) / Bennett, Peter (Committee member) / Treacy, Michael J. (Committee member) / Arizona State University (Publisher)
Created2011
Description
In a conscious effort to combat the low enrollment of women in construction management, a program was created to retain women through a mentorship program - Advancing Women in Construction. A qualitative analysis, facilitated through a grounded theory approach, sought to understand if the program was indeed successful, and what value did the students derive from the programs and participating in the mentoring process.
ContributorsEicher, Matthew (Author) / Wilkinson, Christine Kajikawa (Thesis advisor) / Calleroz-White, Mistalene (Committee member) / Gibson, Jr., G. Edward (Committee member) / Arizona State University (Publisher)
Created2013
Description
Despite the wealth of folk music traditions in Portugal and the importance of the clarinet in the music of bandas filarmonicas, it is uncommon to find works featuring the clarinet using Portuguese folk music elements. In the interest of expanding this type of repertoire, three new works were commissioned from three different composers. The resulting works are Seres Imaginarios 3 by Luis Cardoso; Delirio Barroco by Tiago Derrica; and Memória by Pedro Faria Gomes. In an effort to submit these new works for inclusion into mainstream performance literature, the author has recorded these works on compact disc. This document includes interview transcripts with each composer, providing first-person discussion of each composition, as well as detailed biographical information on each composer. To provide context, the author has included a brief discussion on Portuguese folk music, and in particular, the role that the clarinet plays in Portuguese folk music culture.
ContributorsFerreira, Wesley (Contributor) / Spring, Robert S (Thesis advisor) / Bailey, Wayne (Committee member) / Gardner, Joshua (Committee member) / Hill, Gary (Committee member) / Schuring, Martin (Committee member) / Solis, Theodore (Committee member) / Arizona State University (Publisher)
Created2013
Description
ABTRACT For decades the United States has tried to increase the number of students pursuing science, technology, engineering, and mathematics (STEM) education and careers. Educators and policy makers continue to seek strategies to increase the number of students in the STEM education pipeline. Public institutions of higher education are involved in this effort through education and public outreach (EPO) initiatives. Arizona State University opened its largest research facility, the new Interdisciplinary Science and Technology Building IV (ISTB4) in September, 2012. As the new home of the School of Earth & Space Exploration (SESE), ISTB4 was designed to serve the school's dedication to K-12 education and public outreach. This dissertation presents a menu of ideas for revamping the EPO program for SESE. Utilizing the Delphi method, I was able to clarify which ideas would be most supported, and those that would not, by a variety of important SESE stakeholders. The study revealed that consensus exists in areas related to staffing and expansion of free programming, whereas less consensus exist in the areas of fee-based programs. The following most promising ideas for improving the SESE's EPO effort were identified and will be presented to SESE's incoming director in July, 2013: (a) hire a full-time director, theater manager, and program coordinator; (b) establish a service-learning requirement obligating undergraduate SESE majors to serve as docent support for outreach programs; (c) obligate all EPO operations to advise, assist, and contribute to the development of curricula, activities, and exhibits; (d) perform a market and cost analysis of other informational education venues offering similar programming; (3) establish a schedule of fee-based planetarium and film offerings; and (f) create an ISTB4 centric, fee-based package of programs specifically correlated to K12 education standards that can be delivered as a fieldtrip experience.
ContributorsFisher, Richard D. (Author) / Clark, Christopher M. (Thesis advisor) / Kelley, Michael (Committee member) / Glasper, Rufus (Committee member) / Arizona State University (Publisher)
Created2013
Description
Legislative changes and discussions about the United States falling further and further behind other nations in science, technology, engineering, and math (STEM) achievement are growing. As they grow, STEM instruction in elementary school has earned its place as a national area of interest in education. In the case of Ivory School District, teachers are being asked to radically change their daily practices by consistently implementing inquiry-based STEM experiences in their classrooms. As such, teachers are being asked to scale a divide between the district expectations and their knowledge and experience. Many fourth grade educators are teachers who have been trained as generalists and typically do not have specific background or experience in the philosophy, instructional strategies, or content associated with STEM. Using a prototype approach, this study aims to understand how such teachers conceptualize STEM instruction and the relationship between their experience and conceptions.
ContributorsKenney, Meghan (Author) / Fischman, Gustavo (Thesis advisor) / Powers, Jeanne (Committee member) / Rasch, Katherine D (Committee member) / Arizona State University (Publisher)
Created2013
Description
Historically, African American students have been underrepresented in the fields of science, technology, engineering and mathematics (STEM). If African American students continue to be underrepresented in STEM fields, they will not have access to valuable and high-paying sectors of the economy. Despite the number of African Americans in these fields being disproportionately low, there are still individuals that persist and complete science degrees. The aim of this study was to investigate African American students who excel in science at Arizona State University and examine the barriers and affordances that they encounter on their journey toward graduation. Qualitative research methods were used to address the research question of the study. My methodology included creating a case study to investigate the experiences of eight African American undergraduate college students at Arizona State University. These four male and four female students were excelling sophomores, juniors, or seniors who were majoring in a science field. Two of the males came from lower socioeconomic status (SES) backgrounds, while two of the males were from higher SES backgrounds. The same applied to the four female participants. My research utilized surveys, semistructured interviews, and student observations to collect data that was analyzed and coded to determine common themes and elements that exist between the students. As a result of the data collection opportunities, peer support and financial support were identified as barriers, while, parental support, financial support, peer support, and teacher support were identified as affordances. In analyzing the data, the results indicated that for the student subjects in this study, sex and SES did not have any relationship with the barriers and affordances experienced.
ContributorsBoyce, Quintin (Author) / Scott, Kimberly (Thesis advisor) / Falls, Deanne (Committee member) / Baker, Dale (Committee member) / Arizona State University (Publisher)
Created2012
Description
Latinas and Latinos are currently underrepresented in terms of our 21st century student academic attainment and workforce, compared to the total U.S. Hispanic population. In a field such as mathematical sciences, Hispanic or Latino U.S. citizenship doctoral recipients only accounted for 3.04% in 2009-2010. While there are various initiatives to engage underrepresented STEM populations through education, there is a need to give a voice to the experiences of Latinas and Latinos engaged in such programs. This study explored the experiences of seven Arizona State University undergraduate Latina and Latino Joaquín Bustoz Math-Science Honors Program (JBMSHP) participants as well as examined how the program enhanced their math and science learning experiences. Participants attended either a five-week or eight-week program and ranged in attendance from 2006 to 2011. Students were provided an opportunity to begin university mathematics and science studies before graduating high school. Through a demographic survey and one-on-one guided interview, participants shared their personal journey, their experience in the JBMSHP, and their goals. Using grounded theory, a qualitative research approach, this study focuses on the unique experiences of Latina and Latino participants. Four major themes emerged from the analysis of the data. Each participant applied to the program with a foundation in which they sought to challenge themselves academically through mathematics and/or science. Through their involvement it the JBMSHP, participants recognized benefits during and after the program. All participants recognized the value of these benefits and their participation and praised the program. Overall, the JBMSHP provided the students the resources to grow their academic capital and if they chose seek a STEM related bachelor degree. The results of this study emphasize the need to expand the JBMSHP both within Arizona and nationally. In addition, there is a need to explore the other components of their parent center, the Mathematical, Computational and Modeling Sciences Center (MCMSC), to determine if the suggested pipeline, MCMSC Model for Enhancing the Math and Science Experiences of Latinas and Latinos, can positively impact our 21st century workforce and the dire representational need of Latinas and Latinos in STEM fields.
ContributorsEscontrias, Gabriel (Author) / Turner, Caroline S. (Thesis advisor) / Keller, Gary D. (Committee member) / Calleroz White, Mistalene D. (Committee member) / Arizona State University (Publisher)
Created2012
Description
While deep disciplinary knowledge will be required to develop next-generation clean energy technologies, the skills to work across disciplines and with diverse stakeholders will also be required. Providing authentic and explicit opportunities for graduate students in science, technology, engineering, and math (STEM) to engage in the broader impacts (BI) 0f their research could support the development of these skills. A concurrent mixed methods action research study was conducted to evaluate the effects of a three-part, semi-structured design workshop on clean energy fellows’ knowledgeability of the broader impacts of their research, their identification with the clean energy field, and their ability to develop high-quality educational outreach products. This study was grounded in a sociocultural theory of learning and informed by several conceptual frameworks: situated learning (Lave & Wenger, 1991), communities of practice (Wenger, 1998), and knowledgeability (Wenger-Trayner & Wenger-Trayner, 2015). Quantitative data was collected through a rubric and survey informed by guiding principles from the Broader Impacts Review Document for National Science Foundation Proposals (Center for Advancing Research Impact in Society, 2020). Qualitative data was collected through this survey and a focus group interview. Results demonstrated a significant, strong, and positive correlation between attendance at the design workshop attendance and Product of Lasting Value (PLV) quality. Unfortunately, the lack of respondents in the post-survey prevented the ability to quantify any changes that took place in fellows’ knowledgeability of the BI of their research and their identification with the clean energy field due to the innovation. Yet, results from the focus group interview do show that some fellows experienced increased knowledgeability of the BI of their research and identification with the clean energy field, but these gains were not necessarily due to the PLV Design Workshop.
ContributorsHendrickson, Danica Lyn (Author) / Salik, Steven (Thesis advisor) / Weinberg, Andrea (Committee member) / Garcia, David (Committee member) / Arizona State University (Publisher)
Created2022
Description
While prior diversity management research has extensively focused on having a representative workforce in public organizations, recent discussions on racism and social equity have shed light on the importance of an inclusive work environment, where individuals feel integrated into organizations and involved in organizational processes. Perceived inclusion in the workplace, defined as the extent to which individuals perceive they are part of significant organizational processes, is the core theme of this dissertation. This study focuses on the perceived inclusion of academic scientists in the US. Inclusion of Scholars of Color (SOCs) and women in science is of particular importance given the low representation and retention of SOCs and women as well prolonged marginalization in academic science.This dissertation aims to understand what shapes perceived inclusion in the workplace by looking at how the demographic and social compositions of one’s social environment shape individuals’ perceptions of workplace inclusion. Focusing on race and gender, the dissertation recognizes the relative and contingent relationships among individuals and networks that affect perceived inclusion. To investigate, I ask two key questions, each focusing on different social structures and their interplay:
1. How do different aspects of social structure in networks (demographics, social network structural characteristics, social network compositional characteristics) influence perceived inclusion in the workplace?
2. How do individuals’ demographic attributes shape the impacts of social structures on workplace inclusion?
To explore these questions, I draw from social identity theories, focusing on intergroup relations, and social capital theory to develop hypotheses. To investigate how social network structures shape inclusion in the workplace, I use a 2011 National Science Foundation-funded national survey of Science, Technology, Engineering, and Mathematics (STEM) faculty in four science fields (biology, biochemistry, civil engineering, and mathematics) at diverse types of higher education institutions. I find that perceived inclusion is a function of social network structure, but the effects depend on the demographic characteristics of the individual and the network. I conclude this study with a discussion about the implications of findings for future research and diversity and inclusion policies.
ContributorsJung, Heyjie (Author) / Welch, Eric W (Thesis advisor) / Corley, Elizabeth A (Committee member) / Stritch, Justin M (Committee member) / Melkers, Julia (Committee member) / Arizona State University (Publisher)
Created2022
Description
The aim of this study was to explore how counselors of a science, technology, engineering, and mathematics (STEM) focused out-of-school time (OST) program understood ways to support students’ social-emotional learning (SEL) and STEM identity development, as well as the impact on counselors’ awareness of their own SEL and STEM identity. To do this, I developed the STEM-Social Emotional Learning for Facilitators (STEM-SELF) intervention. The STEM-SELF intervention focused on 1) implementing a series of workshops; 2) engaging counselors in a cycle of praxis as they created and implemented experiences for students; and 3) engaging counselors in reflection on the learning gained within the program context and in their own personal context. For the intervention, I used a professional learning community (PLC) to engage counselors in cycles of praxis and designed learning activities based on Knowles’ (1980) principles of adult learning. The content counselors learned focused on STEM identity theory, the SEL framework developed by the Collaborative for Academic, Social, and Emotional Learning (CASEL), and modification of the Ways of Being model. The design was a primarily qualitative action research study and data collection and analysis happened in stages that aligned with the stages of implementation of the STEM-SELF intervention. Data included counselors' reflective journals and one-on-one interviews; the analysis was based on a reflexive thematic analysis approach. The study concluded that counselors gained confidence in facilitating SEL and STEM identity development activities and their understanding of SEL and STEM identity became more refined. Counselors also reflected that their learning was directly applicable to their contexts outside of the OST program. Additionally, counselors' awareness of their own SEL increased, and their conception of what made someone a “STEM person” changed.
ContributorsBettis, Megan M. (Author) / Markos, Amy (Thesis advisor) / Gomes, Aldrin (Committee member) / Henderson, Bryan (Committee member) / Jimenez-Silva, Margarita (Committee member) / Arizona State University (Publisher)
Created2023