Electrostatic Effects in III-V Semiconductor Based Metal-optical Nanostructures

Electrostatic Effects in III-V Semiconductor Based Metal-optical Nanostructures

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Date: May 2012
Creator: Gryczynski, Karol Grzegorz
Description: The modification of the band edge or emission energy of semiconductor quantum well light emitters due to image charge induced phenomenon is an emerging field of study. This effect observed in quantum well light emitters is critical for all metal-optics based light emitters including plasmonics, or nanometallic electrode based light emitters. This dissertation presents, for the first time, a systematic study of the image charge effect on semiconductor–metal systems. the necessity of introducing the image charge interactions is demonstrated by experiments and mathematical methods for semiconductor-metal image charge interactions are introduced and developed.
Contributing Partner: UNT Libraries
MEASUREMENT OF NANOSTRUCTURES WITH MICROMACHINED MICROSCOPES

MEASUREMENT OF NANOSTRUCTURES WITH MICROMACHINED MICROSCOPES

Date: April 30, 2005
Creator: KINO, G.S. & MOERNER, W.E.
Description: We have made reproducible scanning probes with high efficiency, and predictable and reproducible character-istics. We obtained good efficiency with dimensions well below the diffraction limit, so that rela-tively small laser powers in the milliwatt range can be used. For single frequency operation, only low power is necessary to obtain very high fields for the excitation of well-defined Raman scattering, and to work in a reflection mode with good scanning speeds; obtained predictable results with very high fields suitable for obtaining Raman scattering and two-photon scattering; made a scanning probe mounted on a micromachined cantilever to obtain high definition reflection mode images that can be scanned rapidly;and observed Raman scattering using bowtie antennas with CW excitation.
Contributing Partner: UNT Libraries Government Documents Department
A low-cost approach to fabrication of multinary compounds for energy-related applications

A low-cost approach to fabrication of multinary compounds for energy-related applications

Date: January 3, 2000
Creator: Bhattacharya, R.N. & Deb, S.K.
Description: Non-vacuum electrodeposition and electroless deposition techniques with a potential to prepare large-area uniform precursor films using low-cost source materials and low-cost capital equipment are very attractive for the growth of compound materials for superconductors and photovoltaic applications. In the first part, a low-cost electrodeposition (ED) method will be discussed for fabrication of high-temperature Tl-oxide-based superconductors. In the second part, electrodeposition and electroless deposition of semiconductor Cu-In-Ga-Se thin films will be discussed.
Contributing Partner: UNT Libraries Government Documents Department
Time-Resolved Photoluminescence and Photovoltaics

Time-Resolved Photoluminescence and Photovoltaics

Date: January 1, 2005
Creator: Metzger, W. K.; Ahrenkiel, R. K.; Dippo, P.; Geisz, J.; Wanlass, M. W. & Kurtz, S.
Description: The time-resolved photoluminescence (TRPL) technique and its ability to characterize recombination in bulk photovoltaic semiconductor materials are reviewed. Results from a variety of materials and a few recent studies are summarized and compared.
Contributing Partner: UNT Libraries Government Documents Department
Polymer Based Nanocomposites for Solar Energy Conversion

Polymer Based Nanocomposites for Solar Energy Conversion

Date: January 1, 2005
Creator: Shaheen, S.; Olson, D.; White, M.; Mitchell, W.; Miedaner, A.; Curtis, C. et al.
Description: Organic semiconductor-based photovoltaic devices offer the promise of low cost photovoltaic technology that can be manufactured via large-scale, roll-to-roll printing techniques. Existing organic photovoltaic devices are currently limited to solar power conversion efficiencies of 3?5%. This is because of poor overlap between the absorption spectrum of the organic chromophores and the solar spectrum, non-ideal band alignment between the donor and acceptor species, and low charge carrier mobilities. To address these issues, we are investigating the development of dendrimeric organic semiconductors that are readily synthesized with high purity. They also benefit from optoelectronic properties, such as band gap and band positions, which can be easily tuned by substituting different chemical groups into the molecule. Additionally, we are developing nanostructured oxide/conjugated polymer composite photovoltaics. These composites take advantage of the high electron mobilities attainable in oxide semiconductors and can be fabricated using low-temperature solution-based growth techniques. Here, we discuss the synthesis and preliminary device results of these novel materials and composites.
Contributing Partner: UNT Libraries Government Documents Department
Chromic mechanism in amorphous WO{sub 3} films

Chromic mechanism in amorphous WO{sub 3} films

Date: November 1, 1996
Creator: Zhang, J.G.; Benson, D.K.; Tracy, C.E.; Deb, S.K.; Czanderna, A.W. & Bechinger, C.
Description: The authors propose a new model for the chromic mechanism in amorphous tungsten oxide films (WO{sub 3{minus}y}{center_dot}nH{sub 2}O). This model not only explains a variety of seemingly conflicting experimental results reported in the literature that cannot be explained by existing models, it also has practical implications with respect to improving the coloring efficiency and durability of electrochromic devices. According to this model, a typical as-deposited tungsten oxide film has tungsten mainly in W{sup 6+} and W{sup 4+} states and can be represented as W{sub 1{minus}y}{sup 6+} W{sub y}{sup 4+}O{sub 3{minus}y}{center_dot}nH{sub 2}O. The proposed chromic mechanism is based on the small polaron transition between the charge-induced W{sup 5+} state and the original W{sup 4+} state instead of the W{sup 5+} and W{sup 6+} states as suggested in previous models. The correlation between the electrochromic and photochromic behavior in amorphous tungsten oxide films is also discussed.
Contributing Partner: UNT Libraries Government Documents Department
Advanced numerical methods and software approaches for semiconductor device simulation

Advanced numerical methods and software approaches for semiconductor device simulation

Date: March 23, 2000
Creator: CAREY,GRAHAM F.; PARDHANANI,A.L. & BOVA,STEVEN W.
Description: In this article the authors concisely present several modern strategies that are applicable to drift-dominated carrier transport in higher-order deterministic models such as the drift-diffusion, hydrodynamic, and quantum hydrodynamic systems. The approaches include extensions of upwind and artificial dissipation schemes, generalization of the traditional Scharfetter-Gummel approach, Petrov-Galerkin and streamline-upwind Petrov Galerkin (SUPG), entropy variables, transformations, least-squares mixed methods and other stabilized Galerkin schemes such as Galerkin least squares and discontinuous Galerkin schemes. The treatment is representative rather than an exhaustive review and several schemes are mentioned only briefly with appropriate reference to the literature. Some of the methods have been applied to the semiconductor device problem while others are still in the early stages of development for this class of applications. They have included numerical examples from the recent research tests with some of the methods. A second aspect of the work deals with algorithms that employ unstructured grids in conjunction with adaptive refinement strategies. The full benefits of such approaches have not yet been developed in this application area and they emphasize the need for further work on analysis, data structures and software to support adaptivity. Finally, they briefly consider some aspects of software frameworks. These include dial-an-operator approaches ...
Contributing Partner: UNT Libraries Government Documents Department
Optical Probe for Semiconductor: Cooperative Research and Development Final Report, CRADA Number CRD-06-206

Optical Probe for Semiconductor: Cooperative Research and Development Final Report, CRADA Number CRD-06-206

Date: February 1, 2011
Creator: Sopori, B.
Description: This CRADA involves development of a new semiconductor characterization tool, Optical Probe, which can be commercialized by GT Solar. GT Solar will participate in the design and testing of this instrument that will be developed under an IPP project.
Contributing Partner: UNT Libraries Government Documents Department
High-Performance Nanostructured Coating (Fact Sheet)

High-Performance Nanostructured Coating (Fact Sheet)

Date: September 1, 2012
Creator: Available, Not
Description: The University of California San Diego is one of the 2012 SunShot CSP R&D awardees for their advanced receivers. This fact sheet explains the motivation, description, and impact of the project.
Contributing Partner: UNT Libraries Government Documents Department