Multifunctional Organic-Inorganic Hybrid Nanophotonic Devices (open access)

Multifunctional Organic-Inorganic Hybrid Nanophotonic Devices

The emergence of optical applications, such as lasers, fiber optics, and semiconductor based sources and detectors, has created a drive for smaller and more specialized devices. Nanophotonics is an emerging field of study that encompasses the disciplines of physics, engineering, chemistry, biology, applied sciences and biomedical technology. In particular, nanophotonics explores optical processes on a nanoscale. This dissertation presents nanophotonic applications that incorporate various forms of the organic polymer N-isopropylacrylamide (NIPA) with inorganic semiconductors. This includes the material characterization of NIPA, with such techniques as ellipsometry and dynamic light scattering. Two devices were constructed incorporating the NIPA hydrogel with semiconductors. The first device comprises a PNIPAM-CdTe hybrid material. The PNIPAM is a means for the control of distances between CdTe quantum dots encapsulated within the hydrogel. Controlling the distance between the quantum dots allows for the control of resonant energy transfer between neighboring quantum dots. Whereby, providing a means for controlling the temperature dependent red-shifts in photoluminescent peaks and FWHM. Further, enhancement of photoluminescent due to increased scattering in the medium is shown as a function of temperature. The second device incorporates NIPA into a 2D photonic crystal patterned on GaAs. The refractive index change of the NIPA hydrogel as …
Date: May 2008
Creator: Garner, Brett William
System: The UNT Digital Library
Teenager's doing history out-of-school: An intrinsic case study of situated learning in history. (open access)

Teenager's doing history out-of-school: An intrinsic case study of situated learning in history.

This intrinsic case study documents a community-based history expedition implemented as a project-based, voluntary, out-of-school history activity. The expedition's development was informed by the National Education Association's concept of the intensive study of history, its structure by the history seminary, and its spirit by Webb's account of seminar as history expedition. Specific study objectives included documentation of the planning, implementation, operation, and outcomes of the expedition, as well as the viability of the history expedition as a vehicle for engaging teenagers in the practice of history. Finally, the study examined whether a history expedition might serve as a curriculum of identity. Constructivist philosophy and situated learning theory grounded the analysis and interpretation of the study. Undertaken in North Central Texas, the study followed the experiences of six teenagers engaged as historians who were given one year to research and write a historical monograph. The monograph concerned the last horse cavalry regiment deployed overseas as a mounted combat unit by the U.S. Army during World War II. The study yielded qualitative data in the form of researcher observations, participant interviews, artifacts of participant writing, and participant speeches. In addition, the study includes evaluations of the historical monograph by subject matter experts. …
Date: May 2008
Creator: Johnston, Glenn T.
System: The UNT Digital Library