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Showing 1 to 20 of 32 for “"optical band gap"”.

  1. Processing-composition-structure effects on the optical band gap of KNbO3-based ceramics

    Pascual-Gonzalez, CristinaSheffield Hallam University2017

    This present work is focused on band-gap engineering of solid-solutions based on KNbO3, which was proposed as a promising photoferroelectric (Grinberg et al., 2013). The strategy to narrow the band-gap of the parent KNbO3 (3.22 eV), relies on replacing Nb5+ by lower valence transition metals (Me3+) …

    sheffield-hallam Repository record

  2. An investigation into the effect of process parameters on carbon film physical properties produced by different deposition techniques

    Dehbi-Alaoui, AzzeddineUniversity of Hull1994

    … relatively poor transmission in the visible. The optical band gap is about 1eV. The refractive index is around 2.2 and their hydrogen content is low.When the carbon content in the source gas was reduced by mixing hydrogen with the hydrocarbon used, the transparency, the content of bonded hydrogen …

    hull Repository record

  3. Development of ternary oxides for use in advanced front contacts in cadmium telluride solar cells by magnetron sputtering

    Meysing, Daniel M.Colorado School of Mines. Arthur Lakes Library2015

    … layer was investigated. Important structural, optical, and electronic properties were altered by varying the sputtering ambient composition (oxygen/argon). Incorporation of oxygen in the films causes the films to lose crystallinity and increases the optical band gap through a shift in …

    colo-mines Repository record

  4. Fabrication of Zinc Nitride Thin Films using RF Magnetron Sputtering Deposition for Optoelectronic Applications

    Wen, TingUniversity of Toledo2012

    Zinc nitride thin films possess a small optical band gap with direct transition, low resistivity, high mobility and carrier concentration. Therefore, it may be suitable as an optoelectronic material for infrared sensors, smart windows and energy conversion devices. The objective of this work is to …

    ohiolink Repository record

  5. A Universal Heterostructure for Photonic Integrated Circuit Applications

    Herzinger, Craig MatthewUniversity of Illinois at Urbana-Champaign1993

    … photonic circuits are investigated using an optical 2 x 2 crossbar switch as a case study. The optical characteristics of slab waveguides are investigated as candidate "universal" structures. Different core profiles, core sizes, and cladding arrangements are considered. A reverse-biased laser …

    uiuc Repository record

  6. Synthesis and characterization of transparent conducting oxides for Stark e ect applications in single molecule spectroscopy

    University of Pretoria2019

    … this mechanism requires a Stark cell. The high optical quality required by the SMS procedure demands a very speci c thickness microscope slide at the objective to sample interface. Since no commercial TCOs of this standard were available, we had to synthesize our own and spincoat our SMS setup's …

    pretoria Repository record

  7. Nanostructured nitrogen and carbon codoped TiO2 thin films: synthesis, structural characterization and optoelectronic properties

    Ruzybayev, InciUniversity of Delaware2014

    … The challenge with TiO2 is that the wide band gap (3.00-3.20 eV) absorbs only ultra-violet (UV) photons and only a small percentage of the solar spectrum is in the UV range. There are various ways to overcome the challenge of sensitizing the material to visible light absorption and this …

    udel Repository record

  8. Electrical, electronic and optical properties of MoS2 & WS2

    Tang, Weitao

    … thickness. Their electrical, electronic and optical properties are of great importance for a variety of applications in optoelectronics as light emitters, detectors, and photovoltaic devices. This work focuses on MoS_2 and WS_2, which are two important members of the TMDC class of materials. …

    njit Repository record

  9. Origins and implications of intrinsic stress in hydrogenated amorphous silicon thin films

    Johlin, Eric (Eric Carl)Massachusetts Institute of Technology2012

    … conditions and the resulting structural, optical, and bulk properties of the material. In this work we investigate these correlations for a-Si:H films created using plasma enhanced chemical vapor deposition (PECVD), focusing on the creation of intrinsic stresses within the films. Through …

    mit Repository record

  10. Characterisation of solution processed zinc oxide quasi-superlattice materials for thin film applications

    Buckley, DarraghUniversity College Cork2020

    … measurements, the structural, morphological, optical, electronic and crystallographic properties were investigated. The impact of the number of layer depositions on defect composition, surface roughness, emission spectrum and optical band gap were assessed. The angle-resolved reflectance of …

    cork Repository record

  11. Deposition, Characterization, and Fabrication of a Zinc Oxide Piezoelectric Thin Film Microspeaker Using DC Reactive Sputtering

    Olzick, Adam2012

    … approach was taken and the structural, optical, electrical, and piezoelectric properties of the ZnO were investigated. Scanning electron microscopy, x-ray diffraction, and atomic force microscopy were utilized to discover the ZnO’s structural properties. Using the XRD and SEM, the …

    calpoly Repository record

  12. Fabrication and optimization of light emitting devices with core-shell quantum dots

    Song, Katherine WeiMassachusetts Institute of Technology2013

    … PbS, or another similar compound -- with a wide band-gap "shell" has recently been shown to significantly boost QD-LED performance and yield the most efficient accent QD-LEDs to date. This thesis studies fabrication techniques to make bright, efficient QD-LEDs with these "core-shell" QDs. The …

    mit Repository record

  13. Exploring the Optical and Redox Properties of π-Conjugated Boron Difluoride Formazanate Dyes

    Dhindsa, Jasveer SThe University of Western Ontario2022

    … to modulate the frontier molecular orbitals and band gaps of these systems. The resulting materials are redox-active and exhibit rich optical properties including high molar absorptivities and low band gaps. Chapter 2 describes a series of acceptor-donor-acceptor compounds consisting of BF2 …

    uwo Repository record

  14. Single-step, Atmospheric Pressure Chemical Vapor Deposition of Methylammonium Bismuth Iodide Thin Films

    Chen, Xiao2017

    … for its non-toxic constituents and favorable optical band gap, thus making it a promising light absorber material. However, manufacturing ready, scale-up processes have not been developed for this compound and this presents a significant roadblock in integrating low-cost, non-toxic Bi-based …

    wustl Repository record

  15. Hot-wire chemical vapour deposition of nanocrystalline silicon and silicon nitride : growth mechanisms and filament stability

    Oliphant, Clive JustinUniversity of the Western Cape2012

    … influenced the structural, mechanical and optical properties of nc-Si:H films mostly when the film thickness is below 250 nm. The film stress, optical band gap, refractive index and crystalline volume fraction approached similar values at longer deposition times irrespective of the …

    western-cape Repository record

  16. IIl-nitride nanowires and heterostructures : growth and optical properties on nanoscale

    Zhou, Xiang, Ph. D. Massachusetts Institute of TechnologyMassachusetts Institute of Technology2014

    … light extraction. Material quality and effective band engineering of such III-nitride nanowires are crucial for the design and fabrication of their optoelectronic applications such as LEDs, lasers and photodetectors. In this thesis, we first demonstrate effective control over GaN nanowire size, …

    mit Repository record

  17. Deposition of CoxSy, NixSy MnS and CdS thin films from their alkylthiourea precursors using the Aerosol Assisted Chemical Vapour Desposition (AACVD) technique

    Mgabi, Londiwe Patience2008

    … (UV) - Visible (Vis) spectra for their optical properties and Energy Dispersive X-ray (EDAX) for the composition of the films. Thin film measurement was performed using the Interferometer method. The X-ray diffraction pattern revealed different phases for the metal chalcogenide film, …

    zulu Repository record

  18. Carrier transport in undoped and doped films of amorphous arsenic triselenide

    Sharp, Alan1983

    … 0.3eV, 0.4eV and 0.6eV above the valence band mobility edge is presented. A new analysis is developed from the concept of a thermally activated capture process. This analysis yields a value for the capture coefficient_y of traps 0.6eV above the mobility edge of 1.1 + 0.5 x 10<sup>-7</sup> …

    abertay Repository record

  19. SYNTHESIS AND CHARACTERIZATION OF ZINC OXIDE BASED NANOSTRUCTURES AND COMPOSITES FOR ENERGY RELATED APPLICATIONS

    Al-Asadi, Ahmed2017

    … of ~45 nm and lengths of 1–1.3 µm, with an optical band gap of ~3.61 eV. The NWs growth was successfully achieved on various substrates (e.g silicon dioxide, plastic sheets, copper grid, and carbon nanotube buckypaper). The as-prepared ZnO NWs were found to be photoactive under ultra violet …

    siu-theses Repository record

  20. Electronic transport properties of thin films of amorphous silicon

    Fortuna, Henry1984

    … transient and steady state photoconductivity and optical absorption experiments were carried out on thin films of amorphous Silicon. These measurements reveal wide variations in the electronic transport properties of specimens of amorphous Silicon prepared under seemingly identical deposition …

    abertay Repository record

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