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- Creators: Department of Information Systems
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 paper explores factors to study why the number of students in STEM are not as high as they could be. Based on both Veda and Soumya's personal experiences, factors were chosen to understand their impact on whether a high school student would choose a STEM major in their college of choice, which could lead them to having a career in STEM. The factors explored will be location, grade level, school, parent/guardian involvement, teacher involvement, media influences, and personal interest. Data was collected through surveys sent to both high school and college students. The high school data came solely from schools in the Phoenix area, whereas college students' data came from across the world. These surveys contained questions regarding all of the above factors and were crafted so that we could gain further insight into each factor without producing bias. Each factor had at least one personal experience by either Veda or Soumya. Many of the survey responses gave insight to how and why a student would decide to pursue STEM or why they did pursue STEM. The main implications derived from the study are the following: the importance of a good support network, active parent/guardian and teacher involvement, and specifically active science teacher involvement. Data from both college and high school students showed that students highly valued a science teacher. One recommendation from this thesis is to provide a training for teachers to learn about how to connect concepts they teach to real-world applications. This can be administered through the district so that they may bring in anyone they feel is qualified to teach such topics such as industry professionals or teachers who specialize in teaching STEM. The last recommendation is for parents to participate in a workshop that will inform them of how to be more involved/engaged with their student.
ContributorsPushpraj, Soumya (Co-author) / Inamdar, Veda (Co-author) / Scott, Kimberly (Thesis director) / EscontrÃÂas, Gabriel (Committee member) / Department of Information Systems (Contributor) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
GENDER DIVERSITY IN STEM: Investigation into Gender Implication in Pursuing Computing-related Majors
Description
This research study concerns the issue of gender diversity that still persists in STEM education, especially in computing-related fields. Females are so severely underrepresented in computing education that the diversity in the fields is even less than that in physics in K-12. This research study seeks to address the problem of low female participation in computing-related fields. For the purpose of the study, two versions of surveys were distributed. One was filled out by 94 local elementary school students that mostly in 3rd-4th grade; the other went to 399 college freshmen in W. P. Carey School of Business. It asks questions, including if students are interested in learning STEM, and what reasons explain them having interest or no interest in STEM learning. Meanwhile, the study aims to unveil if there are any gender discrepancies in regards to STEM learning. Besides those dynamics, three factors—attitudes toward learning computer skills, logic, and coding—are examined for indications on students’ interest in STEM learning.
The results suggest no indication that female students are necessarily less interested than male students in studying computing-related majors, despite that female students find working with computers and coding more difficult. Female students have diverse and varied interests that are non-computing-related, which could be an underlying factor that contributes to their “lower” participation in those majors. While self-interest is the key factor that influences students’ decisions in pursuing STEM majors or non-STEM majors, they also consider job market outlook an important factor. Compared to female students, male students tend to cite family influence in deciding whether to study STEM majors. Furthermore, showing positive attitudes toward working with computers, learning new computer skills, and even coding indicates both male and female students’ potential desires to pursue computing-related majors or careers.
The results suggest no indication that female students are necessarily less interested than male students in studying computing-related majors, despite that female students find working with computers and coding more difficult. Female students have diverse and varied interests that are non-computing-related, which could be an underlying factor that contributes to their “lower” participation in those majors. While self-interest is the key factor that influences students’ decisions in pursuing STEM majors or non-STEM majors, they also consider job market outlook an important factor. Compared to female students, male students tend to cite family influence in deciding whether to study STEM majors. Furthermore, showing positive attitudes toward working with computers, learning new computer skills, and even coding indicates both male and female students’ potential desires to pursue computing-related majors or careers.
ContributorsZhou, Xingyan (Author) / Lin, Elva (Suh-Yun) (Thesis director) / Hsiao, Sharon I-Han (Committee member) / WPC Graduate Programs (Contributor) / Department of Information Systems (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
This paper about the Garden Grub concerns the growing Agritech industry along with exposing middle school students to STEM education. Currently over half of America's students are not prepared to be successful in our technology driven world. These students did not have the opportunity to be exposed to many Science, Technology, Engineering, and Math related careers or majors before entering the working world and/or college. These students are unaware of the real-life applications these topics can have and will never have the chance to pursue these fields. Using the Garden Grub, students will be introduced to the world of Agritech and how traditional agriculture is changing in include more technology. The Garden Grub is designed to not only introduce students to STEM in general, but specifically the Agritech Industry. With the Garden Grub kit and instructions students will be able to construct a small device that will monitor the external temperature and the soil moisture of a plant they are growing. For future implementations of the Garden Grub, we will develop a structured lesson plan to teach the users more about the device they are building. This is so in the future users could continue their education in Agritech and STEM because they have more knowledge on the subjects From standalone testing the Garden Grub, the device was able to successfully monitor the lettuce to ensure that it grew successfully. The Garden Grub instructions and kit were tested in a fourth-grade classroom, where college volunteers worked with the students to begin to create their own device. While there was not enough time to successfully complete the product the fourth graders were more interested in STEM than when we first started. Even though they struggled in the beginning, students quickly learned basic concepts , such as +/- circuit power, transfer of data, and sensor connections. More recently we were able to go into a middle school and teach in a classroom with the students who were part of a coding elective course. Since our last outing we were able to update the user manual and prepare more ahead of time. This gave us more time to explain the concepts to the students, along with being able to successful build all of the devices. They began to think of ways that this device could be applicable to their lives along with how the Garden Grub could be improved in the future.
ContributorsWynia, Rachel Marie (Author) / Lin, Elva (Thesis director) / Eakin, Hallie (Committee member) / WPC Graduate Programs (Contributor) / Department of Information Systems (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This podcast focused on the experience of women in the field of STEM and more specifically civil engineering. The episodes will explore three main topics surrounding women in the workforce: how women navigate and succeed in a workforce with a predominantly male presence, whether or not women experience “impostor syndrome”, and how to deal with being undermined in the workforce. Also available on Spotify! https://open.spotify.com/show/6iyemJ08Et4JCEATtlgNls?si=03167fd008e94bb6
ContributorsRivera, Valentina (Author) / DiCaro, Isabella (Co-author) / Hjelsmtad, Keith (Thesis director) / Boyce-Jacino, Katherine (Committee member) / Barrett, The Honors College (Contributor) / Civil, Environmental and Sustainable Eng Program (Contributor)
Created2022-05
Description
The goal of this creative thesis is to focus on the experience of women in the field of STEM and more specifically civil engineering. This project will explore four main topics surrounding women in the workforce: how women navigate and succeed in a workforce with predominant male presence, how women advance their career given the gender barriers of the industry, including motherhood, and “impostor syndrome” in the workforce
ContributorsDiCaro, Isabella (Author) / Rivera, Valentina (Abridger) / Boyce-Jacino, Katherine (Thesis director) / Hjelmstad, Keith (Committee member) / Barrett, The Honors College (Contributor) / Civil, Environmental and Sustainable Eng Program (Contributor)
Created2022-05