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This book introduces the latest methods for the controlled growth of nanomaterial systems. The coverage includes simple and complex nanomaterial systems, ordered nanostructures and complex nanostructure arrays, and the essential conditions for the controlled growth of nanostructures with different morphologies, sizes, compositions, and microstructures. The book also discusses the dynamics of controlled growth and thermodynamic characteristics of two-dimensional nanorestricted systems. The authors introduce various novel synthesis methods for nanomaterials and nanostructures, such as hierarchical growth, heterostructures growth, doping growth and some developing template synthesis methods. In addition to discussing applications, the book reviews developing trends in nanomaterials and nanostructures.
Book Synopsis Controlled Growth Of Nanomaterials by : Lide Zhang
Download or read book Controlled Growth Of Nanomaterials written by Lide Zhang and published by World Scientific. This book was released on 2007-11-12 with total page 479 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the latest methods for the controlled growth of nanomaterial systems. The coverage includes simple and complex nanomaterial systems, ordered nanostructures and complex nanostructure arrays, and the essential conditions for the controlled growth of nanostructures with different morphologies, sizes, compositions, and microstructures. The book also discusses the dynamics of controlled growth and thermodynamic characteristics of two-dimensional nanorestricted systems. The authors introduce various novel synthesis methods for nanomaterials and nanostructures, such as hierarchical growth, heterostructures growth, doping growth and some developing template synthesis methods. In addition to discussing applications, the book reviews developing trends in nanomaterials and nanostructures.
The first step in developing nanoscience and nanotechnology is the production of nanoparticles. Controlled Synthesis of Nanoparticles in Microheterogeneous Systems contains descriptions of one of the most powerful bottom-up methods of synthesizing size controlled and stable nanoparticles. This method is based on the use of surfactant-containing microheterogeneous systems: liquid crystals, monolayers and multilayers, solutions of direct and reversed micelles, direct and reversed vesicles, and water-in-oil and oil-in-water microemulsions. The author is prominent in the field of physico-chemical characterization of microheterogeneous systems and their use as ideal solvent and reaction media for the production and long-term storage of nanomaterials. This is the first book that attempts to unify the knowledge necessary for judicious manipulation of surfactant-based systems and a fine tuning of geometric and physico-chemical properties of nanoparticles of a wide variety of substances. Prof. Turco Liveri has chosen to write an easy-to-read book aiming to be evocative rather than exhaustive. Because of the intense interest in nanoscience and nanomaterials, this book is an important fundamental work that fits ideally into the series Nanostructure Science and Technology and will be useful for a wide range of students and young researchers involved in the study and manipulation of matter at the atomic level.
Book Synopsis Controlled Synthesis of Nanoparticles in Microheterogeneous Systems by : Vincenzo Turco Liveri
Download or read book Controlled Synthesis of Nanoparticles in Microheterogeneous Systems written by Vincenzo Turco Liveri and published by Springer Science & Business Media. This book was released on 2006-01-04 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first step in developing nanoscience and nanotechnology is the production of nanoparticles. Controlled Synthesis of Nanoparticles in Microheterogeneous Systems contains descriptions of one of the most powerful bottom-up methods of synthesizing size controlled and stable nanoparticles. This method is based on the use of surfactant-containing microheterogeneous systems: liquid crystals, monolayers and multilayers, solutions of direct and reversed micelles, direct and reversed vesicles, and water-in-oil and oil-in-water microemulsions. The author is prominent in the field of physico-chemical characterization of microheterogeneous systems and their use as ideal solvent and reaction media for the production and long-term storage of nanomaterials. This is the first book that attempts to unify the knowledge necessary for judicious manipulation of surfactant-based systems and a fine tuning of geometric and physico-chemical properties of nanoparticles of a wide variety of substances. Prof. Turco Liveri has chosen to write an easy-to-read book aiming to be evocative rather than exhaustive. Because of the intense interest in nanoscience and nanomaterials, this book is an important fundamental work that fits ideally into the series Nanostructure Science and Technology and will be useful for a wide range of students and young researchers involved in the study and manipulation of matter at the atomic level.
Since the size, shape, and microstructure of nanocrystalline materials strongly impact physical and chemical properties, the development of new synthetic routes to nanocrystals with controlled composition and morphology is a key objective of the nanomaterials community. This objective is dependent on control of the nucleation and growth mechanisms that occur during the synthetic process, which in turn requires a fundamental understanding of both classical nucleation and growth and non-classical growth processes in nanostructured materials. Recently, a novel growth process called Oriented Attachment (OA) was identified which appears to be a fundamental mechanism during the development of nanoscale materials. OA is a special case of aggregation that provides an important route by which nanocrystals grow, defects are formed, and unique—often symmetry-defying—crystal morphologies can be produced. This growth mechanism involves reversible self-assembly of primary nanocrystals followed by reorientation of the assembled nanoparticles to achieve structural accord at the particle-particle interface, the removal of adsorbates and solvent molecules, and, finally, the irreversible formation of chemical bonds to produce new single crystals, twins, and intergrowths. Crystallization and Growth of Colloidal Nanocrystals provides a current understanding of the mechanisms related to nucleation and growth for use in controlling nanocrystal morphology and physical-chemical properties, and is essential reading for any chemist or materials scientist with an interest in using nanocrystals as building blocks for larger structures. This book provides a compendium for the expert reader as well as an excellent introduction for advanced undergraduate and graduate students seeking a gateway into this dynamic area of research.
Book Synopsis Crystallization and Growth of Colloidal Nanocrystals by : Edson Roberto Leite
Download or read book Crystallization and Growth of Colloidal Nanocrystals written by Edson Roberto Leite and published by Springer Science & Business Media. This book was released on 2011-11-17 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the size, shape, and microstructure of nanocrystalline materials strongly impact physical and chemical properties, the development of new synthetic routes to nanocrystals with controlled composition and morphology is a key objective of the nanomaterials community. This objective is dependent on control of the nucleation and growth mechanisms that occur during the synthetic process, which in turn requires a fundamental understanding of both classical nucleation and growth and non-classical growth processes in nanostructured materials. Recently, a novel growth process called Oriented Attachment (OA) was identified which appears to be a fundamental mechanism during the development of nanoscale materials. OA is a special case of aggregation that provides an important route by which nanocrystals grow, defects are formed, and unique—often symmetry-defying—crystal morphologies can be produced. This growth mechanism involves reversible self-assembly of primary nanocrystals followed by reorientation of the assembled nanoparticles to achieve structural accord at the particle-particle interface, the removal of adsorbates and solvent molecules, and, finally, the irreversible formation of chemical bonds to produce new single crystals, twins, and intergrowths. Crystallization and Growth of Colloidal Nanocrystals provides a current understanding of the mechanisms related to nucleation and growth for use in controlling nanocrystal morphology and physical-chemical properties, and is essential reading for any chemist or materials scientist with an interest in using nanocrystals as building blocks for larger structures. This book provides a compendium for the expert reader as well as an excellent introduction for advanced undergraduate and graduate students seeking a gateway into this dynamic area of research.
Nanotechnology can profoundly benefit our health, environment and everyday life. In order to make this a reality, both technological and theoretical advancements of the nanomaterial synthesis methods are needed. A nanoparticle is one of the fundamental building blocks in nanotechnology and this thesis describes the control of the nucleation, growth and oxidation of titanium particles produced in a pulsed plasma. It will be shown that by controlling the process conditions both the composition (oxidationstate) and size of the particles can be varied. The experimental results are supported by theoretical modeling. If processing conditions are chosen which give a high temperature in the nanoparticle growth environment, oxygen was found to be necessary in order to nucleate the nanoparticles. The two reasons for this are 1: the lower vapor pressure of a titanium oxide cluster compared to a titanium cluster, meaning a lower probability of evaporation, and 2: the ability of a cluster to cool down by ejecting an oxygen atom when an oxygen molecule condenses on its surface. When the oxygen gas flow was slightly increased, the nanoparticle yield and oxidation state increased. A further increase caused a decrease in particle yield which is attributed to a slight oxidation ofthe cathode. By varying the oxygen flow, it was possible to control the oxidation state of the nanoparticles without fully oxidizing the cathode. Pure titanium nanoparticles could not be produced in a high vacuum system because oxygen containing gases such as residual water vapour have a profound influence on nanoparticle yield and composition. In an ultrahigh vacuum system titanium nanoparticles without significantoxygen contamination were produced by reducing the temperature of the growth environment and increasing the pressure of an argon-helium gas mixture within whichthe nanoparticles grew. The dimer formation rate necessary for this is only achievable at higher pressures. After a dimer has formed, it needs to grow by colliding with a titanium atom followed by cooling by collisions with multiple buffer gas atoms. The condensation event heats up the cluster to a temperature much higher than the gas temperature, where it is during a short time susceptible to evaporation. When the clusters’ internal energy has decreased by collisions with the gas to less than the energy required to evaporate a titanium atom, it is temporarily stable until the next condensation event occurs. The temperature difference by which the cluster has to cool down before it is temporarily stable is exactly as many kelvins as the gas temperature.The addition of helium was found to decrease the temperature of the gas, making it possible for nanoparticles of pure titanium to grow. The process window where this is possible was determined and the results presented opens up new possibilities to synthesize particles with a controlled contamination level and deposition rate.The size of the nanoparticles has been controlled by three means. The first is to change the electrical potential around the growth zone, which allows for size (diameter) control in the order of 25 to 75 nm without influencing the oxygen content of the particles. The second means is by increasing the pressure which decreases the ambipolar diffusion rate of the ions resulting in a higher growth material density. By doing this, the particle size can be increased from 50 to 250 nm, however the oxygen content also increases with increasing pressure when this is done in a high vacuum system. The last means of size control was by adding a helium flow to the process where higher flows resulted in smaller nanoparticle sizes. When changing the pressure in high vacuum, the morphology of the nanoparticles could be controlled. At low pressures, highly faceted near spherical particles were produced. Increasing the pressure caused the formation of cubic particles which appear to ‘fracture’ at higher pressures. At the highest pressure investigated, the particles became poly-crystalline with a cauliflower shape and this morphology was attributed to a lowad atom mobility. The ability to control the size, morphology and composition of the nanoparticles determines the success of applying the process to manufacture devices. In related work presented in this thesis it is shown that 150-200 nm molybdenum particles with cauliflower morphology were found to scatter light in which made them useful in photovoltaic applications, and the size of titanium dioxide nanoparticles were found to influence the selectivity of graphene based gas sensors.
Book Synopsis Controlling the growth of nanoparticles produced in a high power pulsed plasma by : Rickard Gunnarsson
Download or read book Controlling the growth of nanoparticles produced in a high power pulsed plasma written by Rickard Gunnarsson and published by Linköping University Electronic Press. This book was released on 2017-12-21 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanotechnology can profoundly benefit our health, environment and everyday life. In order to make this a reality, both technological and theoretical advancements of the nanomaterial synthesis methods are needed. A nanoparticle is one of the fundamental building blocks in nanotechnology and this thesis describes the control of the nucleation, growth and oxidation of titanium particles produced in a pulsed plasma. It will be shown that by controlling the process conditions both the composition (oxidationstate) and size of the particles can be varied. The experimental results are supported by theoretical modeling. If processing conditions are chosen which give a high temperature in the nanoparticle growth environment, oxygen was found to be necessary in order to nucleate the nanoparticles. The two reasons for this are 1: the lower vapor pressure of a titanium oxide cluster compared to a titanium cluster, meaning a lower probability of evaporation, and 2: the ability of a cluster to cool down by ejecting an oxygen atom when an oxygen molecule condenses on its surface. When the oxygen gas flow was slightly increased, the nanoparticle yield and oxidation state increased. A further increase caused a decrease in particle yield which is attributed to a slight oxidation ofthe cathode. By varying the oxygen flow, it was possible to control the oxidation state of the nanoparticles without fully oxidizing the cathode. Pure titanium nanoparticles could not be produced in a high vacuum system because oxygen containing gases such as residual water vapour have a profound influence on nanoparticle yield and composition. In an ultrahigh vacuum system titanium nanoparticles without significantoxygen contamination were produced by reducing the temperature of the growth environment and increasing the pressure of an argon-helium gas mixture within whichthe nanoparticles grew. The dimer formation rate necessary for this is only achievable at higher pressures. After a dimer has formed, it needs to grow by colliding with a titanium atom followed by cooling by collisions with multiple buffer gas atoms. The condensation event heats up the cluster to a temperature much higher than the gas temperature, where it is during a short time susceptible to evaporation. When the clusters’ internal energy has decreased by collisions with the gas to less than the energy required to evaporate a titanium atom, it is temporarily stable until the next condensation event occurs. The temperature difference by which the cluster has to cool down before it is temporarily stable is exactly as many kelvins as the gas temperature.The addition of helium was found to decrease the temperature of the gas, making it possible for nanoparticles of pure titanium to grow. The process window where this is possible was determined and the results presented opens up new possibilities to synthesize particles with a controlled contamination level and deposition rate.The size of the nanoparticles has been controlled by three means. The first is to change the electrical potential around the growth zone, which allows for size (diameter) control in the order of 25 to 75 nm without influencing the oxygen content of the particles. The second means is by increasing the pressure which decreases the ambipolar diffusion rate of the ions resulting in a higher growth material density. By doing this, the particle size can be increased from 50 to 250 nm, however the oxygen content also increases with increasing pressure when this is done in a high vacuum system. The last means of size control was by adding a helium flow to the process where higher flows resulted in smaller nanoparticle sizes. When changing the pressure in high vacuum, the morphology of the nanoparticles could be controlled. At low pressures, highly faceted near spherical particles were produced. Increasing the pressure caused the formation of cubic particles which appear to ‘fracture’ at higher pressures. At the highest pressure investigated, the particles became poly-crystalline with a cauliflower shape and this morphology was attributed to a lowad atom mobility. The ability to control the size, morphology and composition of the nanoparticles determines the success of applying the process to manufacture devices. In related work presented in this thesis it is shown that 150-200 nm molybdenum particles with cauliflower morphology were found to scatter light in which made them useful in photovoltaic applications, and the size of titanium dioxide nanoparticles were found to influence the selectivity of graphene based gas sensors.
This book covers emerging bioinspired green methods for preparing inorganic nanomaterials. The book starts with an introduction to the principles of green chemistry and engineering, and highlights the special properties that nanomaterials possess, their applications and ways to characterise them. It describes conventional methods of synthesising and manufacturing inorganic nanomaterials, and introduces biological and biomimetic/bioinspired synthetic methods as a solution to precisely control nanomaterials and design sustainable manufacturing routes. The book elaborates on various mechanisms and examples of green nanomaterials, including the role of organic matrix and natural self-assembly, and advantages and opportunities with green nanomaterials. Two case studies of magnetic and silica materials are provided for advanced readers. The book is an insightful reference text for researchers focusing on synthetic biology and nanomaterials. It is an essential title for postgraduates and final-year undergraduates studying advanced materials, sustainable engineering or environmental chemistry.
Book Synopsis Green Nanomaterials by : Siddharth V. Patwardhan
Download or read book Green Nanomaterials written by Siddharth V. Patwardhan and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers emerging bioinspired green methods for preparing inorganic nanomaterials. The book starts with an introduction to the principles of green chemistry and engineering, and highlights the special properties that nanomaterials possess, their applications and ways to characterise them. It describes conventional methods of synthesising and manufacturing inorganic nanomaterials, and introduces biological and biomimetic/bioinspired synthetic methods as a solution to precisely control nanomaterials and design sustainable manufacturing routes. The book elaborates on various mechanisms and examples of green nanomaterials, including the role of organic matrix and natural self-assembly, and advantages and opportunities with green nanomaterials. Two case studies of magnetic and silica materials are provided for advanced readers. The book is an insightful reference text for researchers focusing on synthetic biology and nanomaterials. It is an essential title for postgraduates and final-year undergraduates studying advanced materials, sustainable engineering or environmental chemistry.
Emulsions occur either as end products or during the processing of products in a huge range of areas including the food, agrochemical, pharmaceutical, paint and oil industries. Despite over one hundred years of research in the subject, however, a quantitative understanding of emulsions has been lacking. Modern Aspects of Emulsion Science presents a comprehensive description of both the scientific principles in the field and the very latest advances in research in this important area of surface and colloid science. Topics covered include emulsion formation, type, stability (creaming, flocculation, ripening, coalescence), monodisperse and gel emulsions, and applications. Emphasis has been placed on relating the chemistry of the surfactant or protein adsorbed at the oil-water interface to the principles of the physics involved in the bulk emulsion property. The book has been written by a collection of the world's leading experts in the field, and covers both experimental and theoretical approaches. Modern Aspects of Emulsion Science fills a real gap in the market, being the only book of its kind in print. As such it will prove essential reading for graduates and researchers in this subject, in both academia and industry.
Book Synopsis Modern Aspects of Emulsion Science by : Bernard P Binks
Download or read book Modern Aspects of Emulsion Science written by Bernard P Binks and published by Royal Society of Chemistry. This book was released on 2007-10-31 with total page 443 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emulsions occur either as end products or during the processing of products in a huge range of areas including the food, agrochemical, pharmaceutical, paint and oil industries. Despite over one hundred years of research in the subject, however, a quantitative understanding of emulsions has been lacking. Modern Aspects of Emulsion Science presents a comprehensive description of both the scientific principles in the field and the very latest advances in research in this important area of surface and colloid science. Topics covered include emulsion formation, type, stability (creaming, flocculation, ripening, coalescence), monodisperse and gel emulsions, and applications. Emphasis has been placed on relating the chemistry of the surfactant or protein adsorbed at the oil-water interface to the principles of the physics involved in the bulk emulsion property. The book has been written by a collection of the world's leading experts in the field, and covers both experimental and theoretical approaches. Modern Aspects of Emulsion Science fills a real gap in the market, being the only book of its kind in print. As such it will prove essential reading for graduates and researchers in this subject, in both academia and industry.
With this handbook, the distinguished team of editors has combined the expertise of leading nanomaterials scientists to provide the latest overview of this field. They cover the whole spectrum of nanomaterials, ranging from theory, synthesis, properties, characterization to application, including such new developments as quantum dots, nanoparticles, nanoporous materials, nanowires, nanotubes, and nanostructured polymers. The result is recommended reading for everybody working in nanoscience: Newcomers to the field can acquaint themselves with this exciting subject, while specialists will find answers to all their questions as well as helpful suggestions for further research.
Book Synopsis Nanomaterials Chemistry by : C. N. R. Rao
Download or read book Nanomaterials Chemistry written by C. N. R. Rao and published by John Wiley & Sons. This book was released on 2007-09-24 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: With this handbook, the distinguished team of editors has combined the expertise of leading nanomaterials scientists to provide the latest overview of this field. They cover the whole spectrum of nanomaterials, ranging from theory, synthesis, properties, characterization to application, including such new developments as quantum dots, nanoparticles, nanoporous materials, nanowires, nanotubes, and nanostructured polymers. The result is recommended reading for everybody working in nanoscience: Newcomers to the field can acquaint themselves with this exciting subject, while specialists will find answers to all their questions as well as helpful suggestions for further research.
Nanotechnology can profoundly benefit our health, environment and everyday life. In order to make this a reality, both technological and theoretical advancements of the nanomaterial synthesis methods are needed. A nanoparticle is one of the fundamental building blocks in nanotechnology and this thesis describes the control of the nucleation, growth and oxidation of titanium particles produced in a pulsed plasma. It will be shown that by controlling the process conditions both the composition (oxidationstate) and size of the particles can be varied. The experimental results are supported by theoretical modeling. If processing conditions are chosen which give a high temperature in the nanoparticle growth environment, oxygen was found to be necessary in order to nucleate the nanoparticles. The two reasons for this are 1: the lower vapor pressure of a titanium oxide cluster compared to a titanium cluster, meaning a lower probability of evaporation, and 2: the ability of a cluster to cool down by ejecting an oxygen atom when an oxygen molecule condenses on its surface. When the oxygen gas flow was slightly increased, the nanoparticle yield and oxidation state increased. A further increase caused a decrease in particle yield which is attributed to a slight oxidation ofthe cathode. By varying the oxygen flow, it was possible to control the oxidation state of the nanoparticles without fully oxidizing the cathode. Pure titanium nanoparticles could not be produced in a high vacuum system because oxygen containing gases such as residual water vapour have a profound influence on nanoparticle yield and composition. In an ultrahigh vacuum system titanium nanoparticles without significantoxygen contamination were produced by reducing the temperature of the growth environment and increasing the pressure of an argon-helium gas mixture within whichthe nanoparticles grew. The dimer formation rate necessary for this is only achievable at higher pressures. After a dimer has formed, it needs to grow by colliding with a titanium atom followed by cooling by collisions with multiple buffer gas atoms. The condensation event heats up the cluster to a temperature much higher than the gas temperature, where it is during a short time susceptible to evaporation. When the clusters’ internal energy has decreased by collisions with the gas to less than the energy required to evaporate a titanium atom, it is temporarily stable until the next condensation event occurs. The temperature difference by which the cluster has to cool down before it is temporarily stable is exactly as many kelvins as the gas temperature.The addition of helium was found to decrease the temperature of the gas, making it possible for nanoparticles of pure titanium to grow. The process window where this is possible was determined and the results presented opens up new possibilities to synthesize particles with a controlled contamination level and deposition rate.The size of the nanoparticles has been controlled by three means. The first is to change the electrical potential around the growth zone, which allows for size (diameter) control in the order of 25 to 75 nm without influencing the oxygen content of the particles. The second means is by increasing the pressure which decreases the ambipolar diffusion rate of the ions resulting in a higher growth material density. By doing this, the particle size can be increased from 50 to 250 nm, however the oxygen content also increases with increasing pressure when this is done in a high vacuum system. The last means of size control was by adding a helium flow to the process where higher flows resulted in smaller nanoparticle sizes. When changing the pressure in high vacuum, the morphology of the nanoparticles could be controlled. At low pressures, highly faceted near spherical particles were produced. Increasing the pressure caused the formation of cubic particles which appear to ‘fracture’ at higher pressures. At the highest pressure investigated, the particles became poly-crystalline with a cauliflower shape and this morphology was attributed to a lowad atom mobility. The ability to control the size, morphology and composition of the nanoparticles determines the success of applying the process to manufacture devices. In related work presented in this thesis it is shown that 150-200 nm molybdenum particles with cauliflower morphology were found to scatter light in which made them useful in photovoltaic applications, and the size of titanium dioxide nanoparticles were found to influence the selectivity of graphene based gas sensors.
Book Synopsis Controlling the Growth of Nanoparticles Produced in a Highpower Pulsed Plasma by : Rickard Gunnarsson
Download or read book Controlling the Growth of Nanoparticles Produced in a Highpower Pulsed Plasma written by Rickard Gunnarsson and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanotechnology can profoundly benefit our health, environment and everyday life. In order to make this a reality, both technological and theoretical advancements of the nanomaterial synthesis methods are needed. A nanoparticle is one of the fundamental building blocks in nanotechnology and this thesis describes the control of the nucleation, growth and oxidation of titanium particles produced in a pulsed plasma. It will be shown that by controlling the process conditions both the composition (oxidationstate) and size of the particles can be varied. The experimental results are supported by theoretical modeling. If processing conditions are chosen which give a high temperature in the nanoparticle growth environment, oxygen was found to be necessary in order to nucleate the nanoparticles. The two reasons for this are 1: the lower vapor pressure of a titanium oxide cluster compared to a titanium cluster, meaning a lower probability of evaporation, and 2: the ability of a cluster to cool down by ejecting an oxygen atom when an oxygen molecule condenses on its surface. When the oxygen gas flow was slightly increased, the nanoparticle yield and oxidation state increased. A further increase caused a decrease in particle yield which is attributed to a slight oxidation ofthe cathode. By varying the oxygen flow, it was possible to control the oxidation state of the nanoparticles without fully oxidizing the cathode. Pure titanium nanoparticles could not be produced in a high vacuum system because oxygen containing gases such as residual water vapour have a profound influence on nanoparticle yield and composition. In an ultrahigh vacuum system titanium nanoparticles without significantoxygen contamination were produced by reducing the temperature of the growth environment and increasing the pressure of an argon-helium gas mixture within whichthe nanoparticles grew. The dimer formation rate necessary for this is only achievable at higher pressures. After a dimer has formed, it needs to grow by colliding with a titanium atom followed by cooling by collisions with multiple buffer gas atoms. The condensation event heats up the cluster to a temperature much higher than the gas temperature, where it is during a short time susceptible to evaporation. When the clusters’ internal energy has decreased by collisions with the gas to less than the energy required to evaporate a titanium atom, it is temporarily stable until the next condensation event occurs. The temperature difference by which the cluster has to cool down before it is temporarily stable is exactly as many kelvins as the gas temperature.The addition of helium was found to decrease the temperature of the gas, making it possible for nanoparticles of pure titanium to grow. The process window where this is possible was determined and the results presented opens up new possibilities to synthesize particles with a controlled contamination level and deposition rate.The size of the nanoparticles has been controlled by three means. The first is to change the electrical potential around the growth zone, which allows for size (diameter) control in the order of 25 to 75 nm without influencing the oxygen content of the particles. The second means is by increasing the pressure which decreases the ambipolar diffusion rate of the ions resulting in a higher growth material density. By doing this, the particle size can be increased from 50 to 250 nm, however the oxygen content also increases with increasing pressure when this is done in a high vacuum system. The last means of size control was by adding a helium flow to the process where higher flows resulted in smaller nanoparticle sizes. When changing the pressure in high vacuum, the morphology of the nanoparticles could be controlled. At low pressures, highly faceted near spherical particles were produced. Increasing the pressure caused the formation of cubic particles which appear to ‘fracture’ at higher pressures. At the highest pressure investigated, the particles became poly-crystalline with a cauliflower shape and this morphology was attributed to a lowad atom mobility. The ability to control the size, morphology and composition of the nanoparticles determines the success of applying the process to manufacture devices. In related work presented in this thesis it is shown that 150-200 nm molybdenum particles with cauliflower morphology were found to scatter light in which made them useful in photovoltaic applications, and the size of titanium dioxide nanoparticles were found to influence the selectivity of graphene based gas sensors.
This book introduces the latest methods for the controlled growth of nanomaterial systems. The coverage includes simple and complex nanomaterial systems, ordered nanostructures and complex nanostructure arrays, and the essential conditions for the controlled growth of nanostructures with different morphologies, sizes, compositions, and microstructures. The book also discusses the dynamics of controlled growth and thermodynamic characteristics of two-dimensional nanorestricted systems. The authors introduce various novel synthesis methods for nanomaterials and nanostructures, such as hierarchical growth, heterostructures growth, doping growth and some developing template synthesis methods. In addition to discussing applications, the book reviews developing trends in nanomaterials and nanostructures.
Book Synopsis Nanotechnology Challenges by : Joachim Schummer
Download or read book Nanotechnology Challenges written by Joachim Schummer and published by World Scientific. This book was released on 2006 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the latest methods for the controlled growth of nanomaterial systems. The coverage includes simple and complex nanomaterial systems, ordered nanostructures and complex nanostructure arrays, and the essential conditions for the controlled growth of nanostructures with different morphologies, sizes, compositions, and microstructures. The book also discusses the dynamics of controlled growth and thermodynamic characteristics of two-dimensional nanorestricted systems. The authors introduce various novel synthesis methods for nanomaterials and nanostructures, such as hierarchical growth, heterostructures growth, doping growth and some developing template synthesis methods. In addition to discussing applications, the book reviews developing trends in nanomaterials and nanostructures.
This important book focuses on the synthesis and fabrication of nanostructures and nanomaterials, but also includes properties and applications of nanostructures and nanomaterials, particularly inorganic nanomaterials. It provides balanced and comprehensive coverage of the fundamentals and processing techniques with regard to synthesis, characterization, properties, and applications of nanostructures and nanomaterials. Both chemical processing and lithographic techniques are presented in a systematic and coherent manner for the synthesis and fabrication of 0-D, 1-D, and 2-D nanostructures, as well as special nanomaterials such as carbon nanotubes and ordered mesoporous oxides. The book will serve as a general introduction to nanomaterials and nanotechnology for teaching and self-study purposes.
Book Synopsis Nanostructures & Nanomaterials by : Guozhong Cao
Download or read book Nanostructures & Nanomaterials written by Guozhong Cao and published by Imperial College Press. This book was released on 2004 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: This important book focuses on the synthesis and fabrication of nanostructures and nanomaterials, but also includes properties and applications of nanostructures and nanomaterials, particularly inorganic nanomaterials. It provides balanced and comprehensive coverage of the fundamentals and processing techniques with regard to synthesis, characterization, properties, and applications of nanostructures and nanomaterials. Both chemical processing and lithographic techniques are presented in a systematic and coherent manner for the synthesis and fabrication of 0-D, 1-D, and 2-D nanostructures, as well as special nanomaterials such as carbon nanotubes and ordered mesoporous oxides. The book will serve as a general introduction to nanomaterials and nanotechnology for teaching and self-study purposes.
