Download or read book Structural and Optical Characterization of Ion Beam Synthesized Ge Nanocrystals written by Ian David Sharp and published by . This book was released on 2006 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phase and Shape Evolutions of Ion Beam Synthesized Ge Based Nanostructures written by Swanee Shin and published by . This book was released on 2009 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Synthesis and characterization of Ge based nanostructures are presented. Ion beam synthesis of pure Ge nanocrystals by 74Ge+ implantation into a silica matrix is presented and the strategy to narrow the size distribution by controlling the substrate temperature during implantation is discussed. The size distribution of the sputter synthesized Ge nanocrystals is compared with that of ion beam synthesized Ge nanocrystals. Co-implantation of 74Ge and 120Sn forms binary eutectic alloy nanocrystals. The morphology of the nanocrystals is characterized with transmission electron microscopy and the thermodynamic implication of the equilibrium shape is discussed. It is demonstrated that nanocrystals with a metastable state can be formed with a single excimer laser pulse. The detailed structures and crystallinity of both equilibrium and metastable states are characterized using Raman spectroscopy, scanning transmission electron microscopy, and extended x-ray absorption fine structure spectroscopy. Initial composition dependent recovery of the equilibrium crystalline state upon heating of the metastable structure is investigated with ex-situ Raman spectroscopy and in-situ transmission electron microscopy equipped with a heating stage. The observed temperature tuning range extends from near room temperature to over 500 0C depending on the Sn content, indicating metal mediated lowering of the crystallization temperature. The phase maps of each phase transformation step of the GeSn alloy nanocrystals are shown using energy filtered transmission electron microscopy, and the position shift of the bulk plasmon peak is demonstrated. One dimensional binary eutectic alloy nanostructures, GeAu nanowires, are also synthesized and characterized. In GeAu nanowires, composition dependent post-growth engineering produced various types of morphologies due to the effectively infinite length for atomic diffusion in one direction. The possibility of creating nanostructures with a combination of ion beam implantation and electron beam irradiation is visited and remaining issues are discussed.

Download or read book Characterization and Manipulation of Ion Beam Synthesized Germanium Nanocrystals written by Ian David Sharp and published by . This book was released on 2004 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Nc Ge Using Ion Beam Techniques written by Srinivasa Rao Nelamarri and published by LAP Lambert Academic Publishing. This book was released on 2011-09 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present book deals with the synthesis and characterization of Germanium (Ge) nanocrystals prepared by using various deposition methods, annealing processes and swift heavy ion irradiation. Even though different methods have been used to prepare Ge nanocrystals, researchers are looking for more compact and versatile synthesis methods for various industrial applications. Here, we have used Atom Beam Sputtering (ABS), RF sputtering and ion implantation for initial depositions. Subsequently these as-deposited samples were annealed at various temperatures using normal furnace annealing, rapid thermal annealing (RTA), microwave annealing and irradiated with swift heavy ions of various energies and fluences for crystallization. Advantages and limitations of these techniques have been discussed in detail.

Download or read book Synthesis and Characterization of Embedded Ge Nanocrystals written by Qing Xu and published by . This book was released on 2006 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structural Characterization of Germanium and Gold Germanium Nanoclusters Embedded in Silica written by Julian Guzman and published by . This book was released on 2011 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fabrication and structural characterization of ion beam synthesized Ge and Ge-Au nanoclusters embedded in silica is presented. The theory of nanocluster size distribution from ion beam synthesis is discussed and a processing route to narrow the size distribution is investigated. Transmission electron microscopy is used to determine the size distribution of ion beam synthesized Ge nanoclusters embedded in silica. It is demonstrated that implantation at room temperature, liquid nitrogen (LN2) or ramping temperature, i.e., half dose at LN2 temperature immediately followed by half dose at increasing temperature until room temperature is reached, results in a narrow size distribution of particles. However, it is determined that post-growth thermal annealing broadens the size distribution regardless of the implantation condition. High resolution transmission electron microscopy is used to evaluate the crystallinity of the nanoclusters before and after thermal annealing. Ge-Au nanoclusters embedded in silica are fabricated by co-sputtering Au and silica followed by Ge implantation and thermal annealing. Scanning transmission electron microscopy, Raman spectroscopy, and synchrotron X-ray diffraction are used to demonstrate a reversible phase transition in the system. The bi-lobe structure observed after annealing is switched to a homogeneously mixed structure using a 30 ns UV laser pulse. The structure is switched back to bi-lobe by heating at 80 oC. The bi-lobe/homogeneously mixed switching can be performed at least 10 times. The phases present in the bi-lobe and homogeneously mixed structures are evaluated by synchrotron X-ray diffraction. The melting behavior of the Ge-Au nanoclusters is explored by in-situ transmission electron microscopy.

Download or read book Ion Beams in Materials Processing and Analysis written by Bernd Schmidt and published by Springer Science & Business Media. This book was released on 2012-12-13 with total page 425 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive review of ion beam application in modern materials research is provided, including the basics of ion beam physics and technology. The physics of ion-solid interactions for ion implantation, ion beam synthesis, sputtering and nano-patterning is treated in detail. Its applications in materials research, development and analysis, developments of special techniques and interaction mechanisms of ion beams with solid state matter result in the optimization of new material properties, which are discussed thoroughly. Solid-state properties optimization for functional materials such as doped semiconductors and metal layers for nano-electronics, metal alloys, and nano-patterned surfaces is demonstrated. The ion beam is an important tool for both materials processing and analysis. Researchers engaged in solid-state physics and materials research, engineers and technologists in the field of modern functional materials will welcome this text.

Download or read book Study the Structural Properties of Ge Nanoparticles Formed by Ion Implantation and Thermal Annealing in Nitride base Dielectric Matrices written by Sahar Mirzaei and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates the formation of Ge nanoparticles (NPs) in amorphous Si3N4 and SiOxNy by ion implantation and thermal annealing. The structural properties of the NPs were determined using a combination of laboratory and synchrotron based techniques including cross-section transmission electron microscopy (TEM), x-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), Raman spectroscopy measurements and x-ray absorption spectroscopy (XAS). The motivation for this research is that NPs synthesized from Group IV semiconductors, including Ge, show potential for novel electronic and optoelectronic devices. Ge was chosen as the material for this study, mainly due to its very large bulk exciton Bohr radius (Rb̃ 10 nm) and consequently small R/Rb ratio (where R is the NP radius), which increases the quantum confinement regime for optoelectronic applications. Also, Ge NPs embedded in thin dielectric films have exhibited impressive charge storage capabilities, useful in non-volatile memory (NVM) applications. While many studies have focused on the SiO2 matrix, there have been few experimental studies on the growth of Ge NPs in a silicon nitride and silicon oxynitride matrices. The main focus of this project was on the formation of Ge NPs in different Si3N4-based matrices and examining the short range atomic structure of embedded NPs as function of NP size using extended x-ray absorption fine structure (EXAFS). Specifically, four different matrices have considered: PECVD Si3N4, LPCVD Si3N4, PECVD SiO1.67N0.14 and PECVD SiO1.12N0.37. Size evolution and structural properties of NPs were examined as function of implantation conditions and the host matrix. Ge NPs were formed in plasma enhanced chemical vapour deposition (PECVD) Si3N4. Precipitations occurred for Ge concentrations of ≥6 at.%, which suggests the solubility limits of this order. NP size was influenced by Ge concentration and annealing temperature. NP size increased from 2.4 to 4 nm - for samples annealed at 900oC for 1 hour- when concentration was increased from 9 to 12 at.%. Moreover, as annealing temperature was increased from 700 to 900 oC NP size increased from 3 to 4.5 nm (for 12 at.% Ge samples). In general NP diameters were much small compared to SiO2 matrix due to the N content of the system, low diffusivity and large interfacial energy between Ge atoms and Si3N4-based matrices. Unlike PECVD Si3N4, ion beam synthesis of Ge in LPCVD Si3N4 layers resulted in the formation of SiGe NPs. NP size altered from 2.8 to 3.2 nm for 12 at.% Ge concentration samples after annealing temperature was increased from 700 to 900oC. Also, NP size increased from 2.3 to 3.2 nm for samples annealed at 900oC for 1 hour when Ge concentration was increased from 9 to 12 at.%. Complementary XAS techniques (in particular EXAFS), allowed us a precise and better understanding of the structure of embedded SiGe NPs. Since the lattice difference between Ge and SiGe NPs (less than 4%) could not be distinguished by TEM. A phase transition of the matrix was observed for LPCVD and PECVD Si3N4 matrices after annealing at 1100 oC. This significantly lowered crystallization temperature of un-implanted layers (1600-1800oC). Formation of nanosilicide particles, change of stoichiometry and implantation induced-damage are found to be the most likely causes of crystallization. Ge NPs were formed in SiO1.67N0.14 matrix for different Ge concentrations and annealing temperatures. For Ge concentrations from 9 to 12 at.% annealed at 900oC for 1 hour, NP size increased from 3.7 to 4.5 nm. Also, when annealing temperature was increased from 700 to 900oC NP size increased from 4.1 to 4.5 for 12 at.% Ge concentration. We observed that slight amount of the N in the system had a significant effect on NP size similar to PECVD Si3N4. Unlike other examined systems, cavities were formed near the implanted region in SiO1.12N0.37 matrix for different concentrations and annealing temperatures, which could be correlated to the matrix structure and composition or vacancy events after ion implantation. The size, origin and properties of formed cavities are subjects of future work. No phase transition (or long-range diffusivity of Ge atoms) was observed for SiOxNy matrices after annealing at 1100 oC.

Download or read book Umtriebe der Altgl ubigen in Halle written by and published by . This book was released on 1844 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ion Beam Modification of Materials written by J.S. Williams and published by Newnes. This book was released on 2012-12-02 with total page 1157 pages. Available in PDF, EPUB and Kindle. Book excerpt: This conference consisted of 15 oral sessions, including three plenary papers covering areas of general interest, 22 specialist invited papers and 51 contributed presentations as well as three poster sessions. There were several scientific highlights covering a diverse spectrum of materials and ion beam processing methods. These included a wide range of conventional and novel applications such as: optical displays and opto-electronics, motor vehicle and tooling parts, coatings tailored for desired properties, studies of fundamental defect properties, the production of novel (often buried) compounds, and treating biomedical materials. The study of nanocrystals produced by ion implantation in a range of host matrices, particularly for opto-electronics applications, was one especially new and exciting development. Despite several decades of study, major progress was reported at the conference in understanding defect evolution in semiconductors and the role of defects in transient impurity diffusion. The use of implantation to tune or isolate optical devices and in forming optically active centres and waveguides in semiconductors, polymers and oxide ceramics was a major focus of several presentations at the conference. The formation of hard coatings by ion assisted deposition or direct implantation was also an area which showed much recent progress. Ion beam techniques had also developed apace, particularly those based on plasma immersion ion implantation or alternative techniques for large area surface treatment. Finally, the use of ion beams for the direct treatment of cancerous tissue was a particularly novel and interesting application of ion beams.

Download or read book 21st Century Nanoscience A Handbook written by Klaus D. Sattler and published by CRC Press. This book was released on 2019-11-26 with total page 509 pages. Available in PDF, EPUB and Kindle. Book excerpt: This up-to-date reference is the most comprehensive summary of the field of nanoscience and its applications. It begins with fundamental properties at the nanoscale and then goes well beyond into the practical aspects of the design, synthesis, and use of nanomaterials in various industries. It emphasizes the vast strides made in the field over the past decade – the chapters focus on new, promising directions as well as emerging theoretical and experimental methods. The contents incorporate experimental data and graphs where appropriate, as well as supporting tables and figures with a tutorial approach.

Download or read book The Synthesis and Characterization of Germanium Nanoparticles and Nanowires and the Study of Their Potential in Photovoltaics written by Stephen Corey Codoluto and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasing energy demand of an overpopulated society has bolstered the interest in exploring renewable energy forms, one of which is solar energy. Current solar cell technology is neither an efficient nor cost-effective alternative to currently used fossil fuels. Nanostructured semiconductor building blocks are expected to play a central role in the development of next-generation cost-effective solar cell technology. Among the various materials that have been explored and studied, Ge holds particular promise due to it favorable band gap and good transport characteristic. A method to produce colloidal Ge nanocrystals, however, has not yet been established. Colloidal synthesis provides a scalable and cost-effective route to nanocrystalline semiconductor material as building blocks in low-cost PV energy conversion devices. This work describes the synthesis and characterization of Ge nanoparticles and Ge nanowires and their potential applications. Ge nanoparticles, 1.9 - 16.0 nm, are synthesized via colloidal synthesis by reducing germanium iodide using a strong reducing agent in various coordinating solvents. The effects of reaction and injection temperature, reaction time, and initial concentration are studied. A minimum temperature of 250 °C is required to crystallize Ge in a colloidal synthesis, below which only amorphous material is formed. An increase in reaction temperature from 250 to 300 °C has little effect on the final nanocrystal size and structure. A temperature of 200 °C was found to minimize crystal growth defects. Increasing or decreasing the injection temperature increased the crystal defects. The final crystalline products are analyzed using XRD, FTIR, TEM, HR-TEM, SEM, UV-vis spectroscopy, and PL to study oxidation, crystal structure, and optical properties. Spin coated germanium nanoparticles are combined with sputtered a-Si to create a polysilicon-Ge matrix which could direct charge transfer and decrease recombination of photogenerated charges. As a complementary nanocrystalline Ge building block nanowires were also synthesized by the thermal decomposition of DPG and TMG in supercritical hexane using a batch and a semicontinuous supercritical reactor. Up to 210 mg are synthesized and collected using this process with a diameter range of 20 nm to 60 nm and lengths up to 15 [MICRO SIGN]m. The continuously grown nanowire experimental yield is ~35%, compared to the batch experimental yield of 15%. The Ge nanowires were easily extracted from the collection vessel and characterized using TEM, SEM, and XRD to confirm the presence of Ge and to study the structure of the wires.

Download or read book Nano scale Materials written by S. N. Sahu and published by Nova Publishers. This book was released on 2006 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nano-Scale Materials - From Science to Technology

Download or read book 21st Century Nanoscience written by Klaus D. Sattler and published by CRC Press. This book was released on 2022-01-18 with total page 4153 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 21st Century Nanoscience Handbook will be the most comprehensive, up-to-date large reference work for the field of nanoscience. Handbook of Nanophysics, by the same editor, published in the fall of 2010, was embraced as the first comprehensive reference to consider both fundamental and applied aspects of nanophysics. This follow-up project has been conceived as a necessary expansion and full update that considers the significant advances made in the field since 2010. It goes well beyond the physics as warranted by recent developments in the field. Key Features: Provides the most comprehensive, up-to-date large reference work for the field. Chapters written by international experts in the field. Emphasises presentation and real results and applications. This handbook distinguishes itself from other works by its breadth of coverage, readability and timely topics. The intended readership is very broad, from students and instructors to engineers, physicists, chemists, biologists, biomedical researchers, industry professionals, governmental scientists, and others whose work is impacted by nanotechnology. It will be an indispensable resource in academic, government, and industry libraries worldwide. The fields impacted by nanoscience extend from materials science and engineering to biotechnology, biomedical engineering, medicine, electrical engineering, pharmaceutical science, computer technology, aerospace engineering, mechanical engineering, food science, and beyond.

Download or read book Growth and Characterization of GE Nanocrystals written by and published by . This book was released on 1998 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have synthesized Ge nanocrystals of sizes 4, 8, and 12 nm by ion-implanting Ge+ ions into thermally grown Si02 films and subsequent annealing of the films at 8300 C for 30 min in nitrogen. These films were characterized by x-ray, transmission electron microscopy (TEM), and Raman spectroscopy. A distribution of particle size was identified by TEM in a 1 00 nm band below the surface. Particle sizes were estimated by these 3 techniques.

Download or read book Ion Beam Synthesis of Nanocrystals and Quantum Dots in Optical Materials written by and published by . This book was released on 1996 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-dose ion implantation has been used to synthesize a wide range of nanocrystals and quantum dots, and these structures can be encapsulated in a number of host materials using this technique.

Download or read book Radiation Synthesis of Materials and Compounds written by Boris Ildusovich Kharisov and published by CRC Press. This book was released on 2016-04-19 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt: Researchers and engineers working in nuclear laboratories, nuclear electric plants, and elsewhere in the radiochemical industries need a comprehensive handbook describing all possible radiation-chemistry interactions between irradiation and materials, the preparation of materials under distinct radiation types, the possibility of damage of material