Author: Wei Guo
Publisher:
ISBN: 9780549675549
Category : Arsenides
Languages : en
Pages : 244
Book Description
Iron-catalyzed free radical generation has been proposed to contribute to oxidative stress and toxicity upon exposure to ambient particulate and amphibole asbestos fibers. Simple acellular assays were validated and used to show that toxicologically significant amounts of iron can be mobilized from a diverse set of commercial nanotube samples in the presence of ascorbate and the chelating agent ferrozine. The redox activity was examined by plasmid DNA breakage. Techniques were applied to avoid or remove this bioavailable metal. Potentially responsible mechanisms and optimized acid treatment protocols for free metal in "purified" samples are discussed.
Growth of Highly Ordered Indium Arsenide/gallium Arsenide and Indium Gallium Arsenide/gallium Arsenide Quantum Dots on Nano-patterned Substrates by MBE.
Author: Wei Guo
Publisher:
ISBN: 9780549675549
Category : Arsenides
Languages : en
Pages : 244
Book Description
Iron-catalyzed free radical generation has been proposed to contribute to oxidative stress and toxicity upon exposure to ambient particulate and amphibole asbestos fibers. Simple acellular assays were validated and used to show that toxicologically significant amounts of iron can be mobilized from a diverse set of commercial nanotube samples in the presence of ascorbate and the chelating agent ferrozine. The redox activity was examined by plasmid DNA breakage. Techniques were applied to avoid or remove this bioavailable metal. Potentially responsible mechanisms and optimized acid treatment protocols for free metal in "purified" samples are discussed.
Publisher:
ISBN: 9780549675549
Category : Arsenides
Languages : en
Pages : 244
Book Description
Iron-catalyzed free radical generation has been proposed to contribute to oxidative stress and toxicity upon exposure to ambient particulate and amphibole asbestos fibers. Simple acellular assays were validated and used to show that toxicologically significant amounts of iron can be mobilized from a diverse set of commercial nanotube samples in the presence of ascorbate and the chelating agent ferrozine. The redox activity was examined by plasmid DNA breakage. Techniques were applied to avoid or remove this bioavailable metal. Potentially responsible mechanisms and optimized acid treatment protocols for free metal in "purified" samples are discussed.
Chemical Abstracts
Growth and Characterisation of Ordered Indium Arsenide Quantum Dots on Cross-hatch Virtual Substrate
Author:
Publisher:
ISBN:
Category : Indium arsenide
Languages : en
Pages : 230
Book Description
Growth of InAs quantum dots (QDs) on In[subscript x]Ga[subscript 1-x]As/GaAs(001) cross-hatch virtual substrates (VS) has been carried out by molecular beam epitaxy (MBE).A model explaining the origin of QD aligment on the VS is developed. Cross-hatch surface morphology of the VS is studied by atomic force microscopy(AFM), and its origin by cross-sectional transmission electron microscopy(TEM). The cross-hatch VS consist of 50-nm thick In[subscript 0.15]Ga[subscript 0.85]As on GaAs(001).cross-hatch morphology on the surface of the VS is revealed by AFM and its origin from the networks of misfit dislocations (MDs) is confirmed by TEM. Fast Fourier transform(FFT) and line scan analyses indicate that the cross-hatch is aperiodic with different average lateral spacings in the two orthogonal([1-10] and [110]) directions. The strain and In composition of the VS are examined by high resolution X-ray diffraction(HRXRD). It is found that the degree of strain relaxation of the InGaAs layer increases with increasing thickness and In composition. Consequently ,QDs grown on the different InGaAs layers result in different arrangements of QDs on the cross-hatch surface: ordered QDs are obtained when they are grown on partially-relaxed In[subscript 0.15]Ga[subscript 0.85]As (50 nm) layer; and groups of QDs are obtained when they are grown on more relaxed In[subscript 0.15]Ga[subscript 0.85]As (100 and 150 nm) layers. Photoluminescence (PL) measurements qualitatively agree with the HRXRD results. Various growth interruption(GI) times are introduced after the formation of QDs in order to improve QD uniformity. It is found that a 30-second GI time is the optimum value for the growth of InAs QDs on In[subscript 0.15]Ga[subscript 0.85]As/GaAs VS. After InAs QD formation, The QDs are capped with a thin layer of GaAs in order to study the surface evolution with an aim to using it as a template for further QD growth. It is found that nano holes are seen in the middle of the QDs directly grown on GaAs (which has been reported in the literature) but none are seen when the QDs are grown on the cross-hatch VS (which has not been reported). Instead QDs which are nucleated along the [110] direction become less prominent while those nucleated along the [1-10] direction become more prominent. This result is attributed to the insufficient and asymmetry of strain energies in the underlying plane on which QDs are grown.
Publisher:
ISBN:
Category : Indium arsenide
Languages : en
Pages : 230
Book Description
Growth of InAs quantum dots (QDs) on In[subscript x]Ga[subscript 1-x]As/GaAs(001) cross-hatch virtual substrates (VS) has been carried out by molecular beam epitaxy (MBE).A model explaining the origin of QD aligment on the VS is developed. Cross-hatch surface morphology of the VS is studied by atomic force microscopy(AFM), and its origin by cross-sectional transmission electron microscopy(TEM). The cross-hatch VS consist of 50-nm thick In[subscript 0.15]Ga[subscript 0.85]As on GaAs(001).cross-hatch morphology on the surface of the VS is revealed by AFM and its origin from the networks of misfit dislocations (MDs) is confirmed by TEM. Fast Fourier transform(FFT) and line scan analyses indicate that the cross-hatch is aperiodic with different average lateral spacings in the two orthogonal([1-10] and [110]) directions. The strain and In composition of the VS are examined by high resolution X-ray diffraction(HRXRD). It is found that the degree of strain relaxation of the InGaAs layer increases with increasing thickness and In composition. Consequently ,QDs grown on the different InGaAs layers result in different arrangements of QDs on the cross-hatch surface: ordered QDs are obtained when they are grown on partially-relaxed In[subscript 0.15]Ga[subscript 0.85]As (50 nm) layer; and groups of QDs are obtained when they are grown on more relaxed In[subscript 0.15]Ga[subscript 0.85]As (100 and 150 nm) layers. Photoluminescence (PL) measurements qualitatively agree with the HRXRD results. Various growth interruption(GI) times are introduced after the formation of QDs in order to improve QD uniformity. It is found that a 30-second GI time is the optimum value for the growth of InAs QDs on In[subscript 0.15]Ga[subscript 0.85]As/GaAs VS. After InAs QD formation, The QDs are capped with a thin layer of GaAs in order to study the surface evolution with an aim to using it as a template for further QD growth. It is found that nano holes are seen in the middle of the QDs directly grown on GaAs (which has been reported in the literature) but none are seen when the QDs are grown on the cross-hatch VS (which has not been reported). Instead QDs which are nucleated along the [110] direction become less prominent while those nucleated along the [1-10] direction become more prominent. This result is attributed to the insufficient and asymmetry of strain energies in the underlying plane on which QDs are grown.
Dissertation Abstracts International
Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 800
Book Description
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 800
Book Description
Ceramic Abstracts
The Molecular Beam Epitaxial Growth and Characterization of Indium Gallium Arsenide and Silicon Substrates
Electrical & Electronics Abstracts
Author:
Publisher:
ISBN:
Category : Electrical engineering
Languages : en
Pages : 1904
Book Description
Publisher:
ISBN:
Category : Electrical engineering
Languages : en
Pages : 1904
Book Description
International Aerospace Abstracts
Vapor Phase Epitaxial Growth of Gallium Arsenide, Indium Phosphide, and Indium Gallium Arsenide by the Hydride Technique
Author: Lawrence Martin Zinkiewicz
Publisher:
ISBN:
Category : Crystal growth
Languages : en
Pages : 202
Book Description
Publisher:
ISBN:
Category : Crystal growth
Languages : en
Pages : 202
Book Description
Gallium Arsenide and Related Compounds 1993, Proceedings of the 20th INT Symposium, 29 August - 2 September 1993, Freiburg im Braunschweig, Germany
Author: Günter Weimann
Publisher: CRC Press
ISBN: 9780750302951
Category : Technology & Engineering
Languages : en
Pages : 880
Book Description
Gallium Arsenide and Related Compounds 1993 covers III-V compounds from crystal growth of materials to their device applications. Focusing on the fields of optical communications and satellite broadcasting, the book describes the practical applications for GaAs and III-V compounds in devices and circuits, both conventional and those based on quantum effects. It also discusses ultrafast GaAs transistors and integrated circuits, novel laser diodes, and tunneling devices, and considers the direction for future technologies. In addition, this volume addresses the increasing demands of ultra high speed systems that require careful selection of III-V materials to optimize the performance of electronic and optoelectronic components. It is ideal reading for physicists, materials scientists, electrical, and electronics engineers investigating III-V compound materials, properties, and devices.
Publisher: CRC Press
ISBN: 9780750302951
Category : Technology & Engineering
Languages : en
Pages : 880
Book Description
Gallium Arsenide and Related Compounds 1993 covers III-V compounds from crystal growth of materials to their device applications. Focusing on the fields of optical communications and satellite broadcasting, the book describes the practical applications for GaAs and III-V compounds in devices and circuits, both conventional and those based on quantum effects. It also discusses ultrafast GaAs transistors and integrated circuits, novel laser diodes, and tunneling devices, and considers the direction for future technologies. In addition, this volume addresses the increasing demands of ultra high speed systems that require careful selection of III-V materials to optimize the performance of electronic and optoelectronic components. It is ideal reading for physicists, materials scientists, electrical, and electronics engineers investigating III-V compound materials, properties, and devices.