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- Creators: Atkinson, Robert
- Creators: School of International Letters and Cultures
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
This research was intended to investigate the effects of various motivational variables on high school students' declaration of a STEM major in college, focusing on PSEM majors. It made use of data from the High School Longitudinal Study of 2009, including the first and second follow-up years (2011 and 2013). The advantage of this study over others is due to this data set, which was designed to be a representative sample of the national population of US high school students. Effects of motivational factors were considered in the context of demographic groups, with the analysis conducted on PSEM declaration illuminating a problem in the discrepancy between male and female high school students. In general, however, PSEM retention from intention to declaration is abysmal, with only 35% of those students who intended towards PSEM actually enrolling.
ContributorsMangu, Daniel Matei (Author) / Middleton, James (Thesis director) / Ganesh, Tirupalavanam (Committee member) / School of International Letters and Cultures (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
In today's world, technology plays a large role in everyone's life. However, there is a short supply of professionals to fill the roles in the computing field. When examining closer, it is clear that one group has a smaller representation: women. This can be contributed to many factors early in the women's lives and academic careers. In hopes of increasing the number of women computing professionals, this thesis aimed to understand the problem of a lack of women in technology and studied how hackathons could be a possible solution. The research followed Desert Hacks as it examines the typical participants as well as the hackathons effects on women's morale in technology. Two important questions during the investigation were what kind of women are attending hackathons and how do women feel about the technology industry after a hackathon? The results suggested that hackathon had an overall positive effect on women's motivation in the computing field. Additionally, most research participants believed that everyone has the potential to do well in the field and that gender inclusion is important for the industry. This ideology can foster a healthy environment for women to become more motivated in computing. Through these results, hackathons can be seen as another mean to help motivate women in the field and open up the possibility of future studies of women and hackathons.
ContributorsVo, Thong Bach (Author) / Atkinson, Robert (Thesis director) / Chavez-Echeagaray, Maria Elena (Committee member) / Computer Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
People with disabilities are underrepresented in the Science, Technology, Engineering, and Math (STEM) workforce (NSF, 2016). One way to increase representation of people with disabilities in STEM fields is by supporting students with disabilities (SWDs) at the undergraduate level. In undergraduate education in the United States, SWDs represent approximately 19% of the undergraduate community (U.S. Census Bureau, 2021). However, SWDs have lower graduation and retention rates. This is particularly true for STEM majors, where SWDs make up about 9% of the STEM community in higher education. The AAC&U has defined a list of High-Impact Practices (HIPs), which are active learning practices and experiences that encourage deep learning by promoting student engagement, and could ultimately support student retention (AAC&U). To date, student-centered disability research has not explored the extent to which SWDs participate in HIPs. We hypothesized that SWDs are less likely than students without disabilities to be involved in HIPs and that students who identify as having severe disabilities would participate in HIPs at lower rates. In this study, we conducted a national survey to examine involvement in HIPs for students with disabilities in STEM. We found that disability status significantly affects the probability of participation in undergraduate research, but is not a significant factor for participation in most other HIPs. We also found that self-reported severity of disability did not significantly impact participation in HIPs, though we observed trends that students reporting higher severity generally reported lower participation in HIPs. Our open-ended responses did indicate that SWDs still faced barriers to participation in HIPs.
ContributorsPais, Danielle (Author) / Brownell, Sara (Thesis director) / Cooper, Katelyn (Committee member) / Barrett, The Honors College (Contributor) / Historical, Philosophical & Religious Studies, Sch (Contributor) / School of Life Sciences (Contributor) / School of International Letters and Cultures (Contributor)
Created2022-05
Description
American Sign Language (ASL) is used for Deaf and Hard of Hearing (DHH) individuals to communicate and learn in a classroom setting. In ASL, fingerspelling and gestures are two primary components used for communication. Fingerspelling is commonly used for words that do not have a specifically designated sign or gesture. In technical contexts, such as Computer Science curriculum, there are many technical terms that fall under this category. Most of its jargon does not have standardized ASL gestures; therefore, students, educators, and interpreters alike have been reliant on fingerspelling, which poses challenges for all parties. This study investigates the efficacy of both fingerspelling and gestures with fifteen technical terms that do have standardized gestures. The terms’ fingerspelling and gesture are assessed based on preference, ease of use, ease of learning, and time by research subjects who were selected as DHH individuals familiar with ASL.
The data is collected in a series of video recordings by research subjects as well as a post-participation questionnaire. Each research subject has produced thirty total videos, two videos to fingerspell and gesture each technical term. Afterwards, they completed a post-participation questionnaire in which they indicated their preference and how easy it was to learn and use both fingerspelling and gestures. Additionally, the videos have been analyzed to determine the time difference between fingerspelling and gestures. Analysis reveals that gestures are favored over fingerspelling as they are generally preferred, considered easier to learn and use, and faster. These results underscore the significance for standardized gestures in the Computer Science curriculum for accessible learning that enhances communication and promotes inclusion.
ContributorsKarim, Bushra (Author) / Gupta, Sandeep (Thesis director) / Hossain, Sameena (Committee member) / Barrett, The Honors College (Contributor) / Computer Science and Engineering Program (Contributor) / School of International Letters and Cultures (Contributor)
Created2024-05
Description
The purpose of this instructional design and development study was to describe, evaluate and improve the instructional design process and the work of interdisciplinary design teams. A National Science Foundation (NSF) funded, Transforming Undergraduate Education in Science (TUES) project was the foundation for this study. The project developed new curriculum materials to teach learning content in unsaturated soils in undergraduate geotechnical engineering classes, a subset of the civil engineering. The study describes the instructional design (ID) processes employed by the team members as they assess the need, develop the materials, disseminate the learning unit, and evaluate its effectiveness, along with the impact the instructional design process played in the success of the learning materials with regard to student achievement and faculty and student attitudes. Learning data were collected from undergraduate geotechnical engineering classes from eight partner universities across the country and Puerto Rico over three phases of implementation. Data were collected from students and faculty that included pretest/posttest scores and attitudinal survey questions. The findings indicated a significant growth in the learning with the students of the faculty who were provided all learning materials. The findings also indicated an overall faculty and student satisfaction with the instructional materials. Observational and anecdotal data were also collected in the form of team meeting notes, personal observations, interviews and design logs. Findings of these data indicated a preference with working on an interdisciplinary instructional design team. All these data assisted in the analysis of the ID process, providing a basis for descriptive and inferential data used to provide suggestions for improving the ID process and the work of interdisciplinary instructional design teams.
ContributorsOrnelas, Arthur (Author) / Savenye, Wilhelmina C. (Thesis advisor) / Atkinson, Robert (Committee member) / Bitter, Gary (Committee member) / Houston, Sandra (Committee member) / Arizona State University (Publisher)
Created2015
Description
Guitar Hero III and similar games potentially offer a vehicle for improvement of musical rhythmic accuracy with training delivered in both visual and auditory formats and by use of its novel guitar-shaped interface; however, some theories regarding multimedia learning suggest sound is a possible source of extraneous cognitive load while playing so players may score higher with sound turned off. Also, existing studies have shown that differences in the physical format of interfaces affect learning outcomes. This study sought to determine whether (a) the game’s audio content affects rhythmic accuracy, and (b) the type of game controller used affects learning of rhythmic accuracy. One hundred participants were randomly assigned in approximately equal numbers (ns = 25) to the four cells of a 2x2 between-subjects design. The first variable was the audio content of the game with two levels: on or off. The second variable was the type of game controller: the standard guitar-style controller or tablet interface. Participants across all conditions completed a pre- and post-test with a system that required them to tap along with repeated rhythmic patterns on an electronic drum pad. Statistical evidence showed better outcomes with a tablet controller with respect to input time error, reduction of extra notes played, and reduction of missed notes; however, the guitar-style controller produced superior outcomes in terms of avoiding missed notes and was associated with higher satisfaction by participants. When audio was present better outcomes were achieved at multiple factor-levels of reduction of missed responses, but superior outcomes in input time error were seen without audio. There was no evidence to suggest an interaction between controller type and the presence or absence of audio.
ContributorsThomas, James William (Author) / Zuiker, Steven J (Thesis advisor) / Atkinson, Robert (Thesis advisor) / Savenye, Wilhelmina C (Committee member) / Arizona State University (Publisher)
Created2017