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- All Subjects: mobility
- Creators: Alonzi, Elise
Description
Mobility is an important aspect of the lives of religious individuals described by medieval texts in early and late medieval Ireland, and biogeochemical methods can be used to detect mobility in archaeological populations. Stories are recorded of monks and nuns traveling and founding monasteries across Ireland, Scotland, England, Wales, and other areas of Europe. However, these texts rarely address the quotidian lives of average monks and nuns who lived in monastic communities. This dissertation seeks to understand if travel was a typical part of the experiences of religious and lay people in early and late medieval Ireland. It also aims to increase understanding of how monastic communities related to the local lay communities, including addressing if the monastery was populated by those who grew up in the local area. Another methodological aim of this dissertation is to advance the field of archaeological biogeochemistry by (1) adding to the bioavailable strontium baseline in Ireland and (2) quantifying the contribution of ocean-derived strontium to coastal environments. These topics are explored through the biogeochemical analysis of 88 individuals buried at 5 early and late medieval monasteries in Ireland and the analysis of a total of 85 plant samples from four counties in Ireland. The three papers in this dissertation present: (1) a summary of the mobility of religious and lay people buried at the monasteries (Chapter 2), (2) a case study presenting evidence for fosterage of a local child at the early medieval monastery of Illaunloughan, Co. Kerry (Chapter 3), and (3) a study designed to quantify the impact of sea spray on bioavailable strontium in coastal environments (Chapter 4). The majority of lay and religious individuals studied were estimated to be local, indicating that medieval Irish Christianity was strongly rooted in the local community. The study of ocean-derived strontium in a coastal environment indicates that sea spray has a non-uniform impact on bioavailable strontium in coastal regions. These findings shed new light on medieval monastic and lay life in Ireland through the application of biogeochemical methods, contributing to the growth of the field of archaeological chemistry in Ireland.
ContributorsAlonzi, Elise (Author) / Knudson, Kelly (Thesis advisor) / Hegmon, Michelle (Committee member) / Scott, Rachel (Committee member) / Stojanowski, Christopher (Committee member) / Arizona State University (Publisher)
Created2018
Description
The first part of this dissertation reports the study of the vertical carrier transport and device application in InAs/InAs1-xSbx strain-balanced type-II superlattice. It is known that the low hole mobility in the InAs/InAs1-xSbx superlattice is considered as the main reason for the low internal quantum efficiency of its mid-wave and long-wave infrared photodetectors, compared with that of its HgCdTe counterparts. Optical measurements using time-resolved photoluminescence and steady-state photoluminescence spectroscopy are implemented to extract the diffusion coefficients and mobilities of holes in the superlattices at various temperatures from 12 K to 210 K. The sample structure consists of a mid-wave infrared superlattice absorber region grown atop a long-wave infrared superlattice probe region. An ambipolar diffusion model is adopted to extract the hole mobility. The results show that the hole mobility first increases from 0.2 cm2/Vs at 12 K and then levels off at ~50 cm2/Vs as the temperature exceeds ~60 K. An InAs/InAs1-xSbx type-II superlattice nBn long-wavelength barrier infrared photodetector has also been demonstrated with a measured dark current density of 9.5×10-4 A/cm2 and a maximum resistance-area product of 563 Ω-cm2 at 77 K under a bias of -0.5 V. The Arrhenius plot of the dark current density reveals a possible high-operating-temperature of 110 K.The second part of the dissertation reports a lift-off technology using a water-soluble sacrificial MgTe layer grown on InSb. This technique enables the seamless integration of materials with lattice constants near 6.5 Å, such as InSb, CdTe, PbTe, HgTe and Sn. Coherently strained MgTe with a lattice constant close to 6.5 Å acts as a sacrificial layer which reacts with water and releases the film above it. Freestanding CdTe/MgxCd1-xTe double-heterostructures resulting from the lift-off process show increased photoluminescence intensity due to enhanced extraction efficiency and photon-recycling effect. The lifted-off thin films show smooth and flat surfaces with 6.7 Å root-mean-square roughness revealed by atomic-force microscopy profiles. The increased photoluminescence intensity also confirms that the CdTe/MgxCd1-xTe double-heterostructures maintain the high optical quality after epitaxial lift-off.
ContributorsTsai, Cheng-Ying (Author) / Zhang, Yong-Hang YZ (Thesis advisor) / Vasileska, Dragica DV (Committee member) / Johnson, Shane SJ (Committee member) / Zhao, Yuji YZ (Committee member) / Arizona State University (Publisher)
Created2020