Home  About us  Contact
 

Oxygen Incorporation (oxygen + incorporation)

Distribution by Scientific Domains
Physics and Astronomy57%

Selected Abstracts

Polymerization in Nanocrystalline Diamond Films by Oxygen Incorporation

PLASMA PROCESSES AND POLYMERS, Issue 9 2006
Kungen Teii
Abstract Summary: Structure and resistivity of nanocrystalline diamond films deposited using microwave Ar-rich/O2/CH4 plasmas have been examined as a function of the O2/CH4 ratio from 0 to 0.53. Addition of O2 to Ar-rich/CH4 plasmas likely reduced the density of C2 radicals due to loss reactions of O atoms with CH4 and CHx radicals. The Raman peak of diamond at 1,332 cm,1 was overlapped by the D peak of sp2 -bonded, disordered carbon and its intensity was a little enhanced by the O2 addition, while the average size of sp2 -bonded carbon clusters in nondiamond phases was increased. Oxygen was incorporated into the films in forms of CO bonds, which bridged the carbon clusters themselves, and formed polymer-like, large-unit structures. The resistivity of the films was drastically increased from the order of 10,4 up to 104 ,,·,m with a small O2 addition (1.2 vol.-% in total pressure), providing novel sensor and storage applications based on oxygen incorporation and desorption. Decomposition of a Raman spectrum showing the diamond, D and G modes of amorphous carbon, and trans -polyacetylene peaks. The insert represents a typical SEM image showing a film surface. [source]

Dielectric layers for organic field effect transistors as gate dielectric and surface passivation

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2008
T. Diekmann
Abstract Organic field effect transistors with the organic semiconductor pentacene, using silicon substrates, were successfully built on conventional inorganic dielectrics like silicon dioxide or silicon nitride. They can drive drain currents up to 15 mA. Beyond that, polymer films were investigated as gate dielectrics in order to achieve transistors on plastic films. On polyester substrates with an inorganic,organic gate dielectric, devices reach drain currents comparable to transistors on silicon dioxide and charge carrier mobilities of up to 0.35 cm2/V s. Analysis of the pentacene surface by atomic force microscopy showed pentacene crystallites achieving dimensions of more than 1.5 µm. The unprotected organic devices suffer from degradation due to water and oxygen incorporation. Therefore, the application of a hydrophobic polytetrafluoroethylene layer as capping layer is studied. Because of the reduced influence of water, a shift to positive threshold voltages is caused. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Origins of n-type residual carriers in RF-MOMBE grown InN layers

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2007
Kosuke Iwao
Abstract We have investigated quantitatively on the origins of residual electrons in InN layers to make clear some roles of oxygen incorporation for band-gap widening. It has been found out that a linear relation was observed between oxygen and residual electron concentrations for InN layers grown by RF-MOMBE using TMIn source, although the residual electron concentration is super-linearly dependent on oxygen concentration for InN layers grown by RF-MBE using metal In source. The experimental results strongly indicate that oxygen atoms and/or nitrogen vacancies induced by oxygen incorporation are major origins of the residual carrier concentrations. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Investigation of oxygen incorporation in AlGaN/GaN heterostructures

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2003
Ho Won Jang
Abstract The unintentional doping of oxygen atoms in undoped AlGaN layers was demonstrated by scanning photoemission microscopy (SPEM) using synchrotron radiation. In-situ annealing at 1000 °C and subsequent SPEM imaging showed that the oxygen concentration in AlGaN was much higher than in GaN. Space-resolved photoemission spectra of O 1s, Ga 3d and Al 2p core levels showed that the predominant oxygen incorporation in AlGaN resulted from the formation of Al,O bonds due to the high reactivity of Al with oxygen. The degenerated AlGaN layer produced by the oxygen donors caused the tunneling-assisted transport of electrons at the interface of the AlGaN with metal contacts and an increase in the sheet carrier concentration at the AlGaN/GaN heterointerface. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Polymerization in Nanocrystalline Diamond Films by Oxygen Incorporation

PLASMA PROCESSES AND POLYMERS, Issue 9 2006
Kungen Teii
Abstract Summary: Structure and resistivity of nanocrystalline diamond films deposited using microwave Ar-rich/O2/CH4 plasmas have been examined as a function of the O2/CH4 ratio from 0 to 0.53. Addition of O2 to Ar-rich/CH4 plasmas likely reduced the density of C2 radicals due to loss reactions of O atoms with CH4 and CHx radicals. The Raman peak of diamond at 1,332 cm,1 was overlapped by the D peak of sp2 -bonded, disordered carbon and its intensity was a little enhanced by the O2 addition, while the average size of sp2 -bonded carbon clusters in nondiamond phases was increased. Oxygen was incorporated into the films in forms of CO bonds, which bridged the carbon clusters themselves, and formed polymer-like, large-unit structures. The resistivity of the films was drastically increased from the order of 10,4 up to 104 ,,·,m with a small O2 addition (1.2 vol.-% in total pressure), providing novel sensor and storage applications based on oxygen incorporation and desorption. Decomposition of a Raman spectrum showing the diamond, D and G modes of amorphous carbon, and trans -polyacetylene peaks. The insert represents a typical SEM image showing a film surface. [source]

Structures of the multicomponent Rieske non-heme iron toluene 2,3-dioxygenase enzyme system

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2009
Rosmarie Friemann
Bacterial Rieske non-heme iron oxygenases catalyze the initial hydroxylation of aromatic hydrocarbon substrates. The structures of all three components of one such system, the toluene 2,3-dioxygenase system, have now been determined. This system consists of a reductase, a ferredoxin and a terminal dioxygenase. The dioxygenase, which was cocrystallized with toluene, is a heterohexamer containing a catalytic and a structural subunit. The catalytic subunit contains a Rieske [2Fe,2S] cluster and mononuclear iron at the active site. This iron is not strongly bound and is easily removed during enzyme purification. The structures of the enzyme with and without mononuclear iron demonstrate that part of the structure is flexible in the absence of iron. The orientation of the toluene substrate in the active site is consistent with the regiospecificity of oxygen incorporation seen in the product formed. The ferredoxin is Rieske type and contains a [2Fe,2S] cluster close to the protein surface. The reductase belongs to the glutathione reductase family of flavoenzymes and consists of three domains: an FAD-binding domain, an NADH-binding domain and a C-terminal domain. A model for electron transfer from NADH via FAD in the reductase and the ferredoxin to the terminal active-site mononuclear iron of the dioxygenase is proposed. [source]