Matching Items (73)
Description
Infrared photodetectors, used in applications for sensing and imaging, such as military target recognition, chemical/gas detection, and night vision enhancement, are predominantly comprised of an expensive II-VI material, HgCdTe. III-V type-II superlattices (SLs) have been studied as viable alternatives for HgCdTe due to the SL advantages over HgCdTe: greater control of the alloy composition, resulting in more uniform materials and cutoff wavelengths across the wafer; stronger bonds and structural stability; less expensive substrates, i.e., GaSb; mature III-V growth and processing technologies; lower band-to-band tunneling due to larger electron effective masses; and reduced Auger recombination enabling operation at higher temperatures and longer wavelengths. However, the dark current of InAs/Ga1-xInxSb SL detectors is higher than that of HgCdTe detectors and limited by Shockley-Read-Hall (SRH) recombination rather than Auger recombination. This dissertation work focuses on InAs/InAs1-xSbx SLs, another promising alternative for infrared laser and detector applications due to possible lower SRH recombination and the absence of gallium, which simplifies the SL interfaces and growth processes. InAs/InAs1-xSbx SLs strain-balanced to GaSb substrates were designed for the mid- and long-wavelength infrared (MWIR and LWIR) spectral ranges and were grown using MOCVD and MBE by various groups. Detailed characterization using high-resolution x-ray diffraction, atomic force microscopy, photoluminescence (PL), and photoconductance revealed the excellent structural and optical properties of the MBE materials. Two key material parameters were studied in detail: the valence band offset (VBO) and minority carrier lifetime. The VBO between InAs and InAs1-xSbx strained on GaSb with x = 0.28 - 0.41 was best described by Qv = ÄEv/ÄEg = 1.75 ± 0.03. Time-resolved PL experiments on a LWIR SL revealed a lifetime of 412 ns at 77 K, one order of magnitude greater than that of InAs/Ga1-xInxSb LWIR SLs due to less SRH recombination. MWIR SLs also had 100's of ns lifetimes that were dominated by radiative recombination due to shorter periods and larger wave function overlaps. These results allow InAs/InAs1-xSbx SLs to be designed for LWIR photodetectors with minority carrier lifetimes approaching those of HgCdTe, lower dark currents, and higher operating temperatures.
ContributorsSteenbergen, Elizabeth H (Author) / Zhang, Yong-Hang (Thesis advisor) / Brown, Gail J. (Committee member) / Vasileska, Dragica (Committee member) / Johnson, Shane R. (Committee member) / Arizona State University (Publisher)
Created2012
Description
The Rio Salado Project began in the College of Architecture in the fall of 1966 when Dean James Elmore proposed to the studio faculty "Let's do something with the (Salt) River." This is a collection of videos describing the progress of the project since students presented their work over 50 years ago. The most prominent development is the Tempe Town Lake.
ContributorsElmore, James (Narrator, Originator) / Herberger Institute School of Dance (Producer)
Created1995-10-01
Description
Background: It is estimated that 50% of all mental illness arises prior to age 14, an incident attributed in part to disruptions and imbalances within the family system. Equine assisted learning is a complementary and alternative approach to family therapy which is being used increasingly to promote mental health in both adults and children. This study sought to build and deliver an evidence-based, family-centered equine assisted learning program aimed at promoting family function, family satisfaction and child social-emotional competence, and to measure its acceptability and preliminary effect.
Method: Twenty families with children 10 years and older were recruited to participate in a 3-week equine assisted learning program at a therapeutic riding center in Phoenix, Arizona. Sessions included groundwork activities with horses used to promote life skills using experiential learning theory. The study design included a mixed-method quasi-experimental one-group pretest posttest design using the following mental health instruments: Devereaux Student Strengths Assessment, Brief Family Assessment Measure (3 dimensions), and Family Satisfaction Scale to measure child social-emotional competence, family function, and family satisfaction, respectively. Acceptability was determined using a Likert-type questionnaire with open-ended questions to gain a qualitative thematic perspective of the experience.
Results: Preliminary pretest and posttest comparisons were statistically significant for improvements in family satisfaction (p = 0.001, M = -5.84, SD = 5.63), all three domains of family function (General Scale: p = 0.005, M = 6.84, SD = 9.20; Self-Rating Scale: p = 0.050, M = 6.53, SD = 12.89; and Dyadic Relationship Scale: p = 0.028, M = 3.47, SD = 7.18), and child social-emotional competence (p = 0.015, M = -4.05, SD 5.95). Effect sizes were moderate to large (d > 0.5) for all but one instrument (Self-Rating Scale), suggesting a considerable magnitude of change over the three-week period. The intervention was highly accepted among both children and adults. Themes of proximity, self-discovery, and regard for others emerged during evaluation of qualitative findings. Longitudinal comparisons of baseline and 3-month follow-up remain in-progress, a topic available for future discussion.
Discussion: Results help to validate equine assisted learning as a valuable tool in the promotion of child social-emotional intelligence strengthened in part by the promotion of family function and family satisfaction. For mental health professionals, these results serve as a reminder of the alternatives that are available, as well as the importance of partnerships within the community. For therapeutic riding centers, these results help equine professionals validate their programs and gain a foothold within the scientific community. Additionally, they invite future riding centers to follow course in incorporating evidence into their programs and examining new directions for growth within the mental health community.
Method: Twenty families with children 10 years and older were recruited to participate in a 3-week equine assisted learning program at a therapeutic riding center in Phoenix, Arizona. Sessions included groundwork activities with horses used to promote life skills using experiential learning theory. The study design included a mixed-method quasi-experimental one-group pretest posttest design using the following mental health instruments: Devereaux Student Strengths Assessment, Brief Family Assessment Measure (3 dimensions), and Family Satisfaction Scale to measure child social-emotional competence, family function, and family satisfaction, respectively. Acceptability was determined using a Likert-type questionnaire with open-ended questions to gain a qualitative thematic perspective of the experience.
Results: Preliminary pretest and posttest comparisons were statistically significant for improvements in family satisfaction (p = 0.001, M = -5.84, SD = 5.63), all three domains of family function (General Scale: p = 0.005, M = 6.84, SD = 9.20; Self-Rating Scale: p = 0.050, M = 6.53, SD = 12.89; and Dyadic Relationship Scale: p = 0.028, M = 3.47, SD = 7.18), and child social-emotional competence (p = 0.015, M = -4.05, SD 5.95). Effect sizes were moderate to large (d > 0.5) for all but one instrument (Self-Rating Scale), suggesting a considerable magnitude of change over the three-week period. The intervention was highly accepted among both children and adults. Themes of proximity, self-discovery, and regard for others emerged during evaluation of qualitative findings. Longitudinal comparisons of baseline and 3-month follow-up remain in-progress, a topic available for future discussion.
Discussion: Results help to validate equine assisted learning as a valuable tool in the promotion of child social-emotional intelligence strengthened in part by the promotion of family function and family satisfaction. For mental health professionals, these results serve as a reminder of the alternatives that are available, as well as the importance of partnerships within the community. For therapeutic riding centers, these results help equine professionals validate their programs and gain a foothold within the scientific community. Additionally, they invite future riding centers to follow course in incorporating evidence into their programs and examining new directions for growth within the mental health community.
ContributorsSolarz, Allison (Author) / Chen, Angela (Thesis advisor)
Created2019-05-02
ContributorsLi, Jing-Jing (Author) / Liu, Xinyu (Author) / Liu, Shi (Author) / Wang, Shumin (Author) / Smith, David J. (Author) / Ding, Ding (Author) / Johnson, Shane R. (Author) / Furdyna, Jacek K. (Author) / Zhang, Yong-Hang (Author)
Created2012
ContributorsBlume, G (Author) / Hild, Konstanze (Author) / Marko, I. P. (Author) / Hosea, T. J. C. (Author) / Yu, S.-Q. (Author) / Chaparro, S. A. (Author) / Samal, N. (Author) / Johnson, Shane R. (Author) / Zhang, Yong-Hang (Author) / Sweeney, S. J. (Author)
Created2012
ContributorsLi, Jing-Jing (Author) / Yin, Leijun (Author) / Johnson, Shane R. (Author) / Skromme, B. J. (Author) / Wang, Shumin (Author) / Liu, Xinyu (Author) / Ding, Ding (Author) / Ning, Cun-Zheng (Author) / Furdyna, Jacek K. (Author) / Zhang, Yong-Hang (Author)
Created2012
ContributorsHossain, N (Author) / Hild, Konstanze (Author) / Jin, S. R. (Author) / Yu, S.-Q. (Author) / Johnson, Shane R. (Author) / Ding, Ding (Author) / Zhang, Yong-Hang (Author) / Sweeney, S. J. (Author)
Created2013
ContributorsLiu, Shi (Author) / Li, Hua (Author) / Cellek, Oray O. (Author) / Ding, Ding (Author) / Shen, Xiao-Meng (Author) / Lin, Zhi-Yuan (Author) / Steenbergen, Elizabeth H. (Author) / Fan, Jin (Author) / He, Zhao-Yu (Author) / Lu, Jing (Author) / Johnson, Shane R. (Author) / Smith, David J. (Author) / Zhang, Yong-Hang (Author)
Created2013
ContributorsWebster, Preston T. (Author) / Riordan, Nathaniel A. (Author) / Gogineni, Chaturvedi (Author) / Liu, Shi (Author) / Lu, Jing (Author) / Zhao, Xin-Hao (Author) / Smith, David J. (Author) / Zhang, Yong-Hang (Author) / Johnson, Shane R. (Author)
Created2014
ContributorsBeaudoin, M. (Author) / Johnson, Shane R. (Author) / Boonzaayer, Martin D. (Author) / Zhang, Yong-Hang (Author) / Johs, B. (Author)
Created1999