Download or read book Control of Structural Properties in Strontium Titanate Thin Films Grown by Liquid delivery Spin Metal organic Vapor Phase Epitaxy written by Aykut Baki and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metalorganic Vapor Phase Epitaxy MOVPE written by Stuart Irvine and published by John Wiley & Sons. This book was released on 2019-10-07 with total page 582 pages. Available in PDF, EPUB and Kindle. Book excerpt: Systematically discusses the growth method, material properties, and applications for key semiconductor materials MOVPE is a chemical vapor deposition technique that produces single or polycrystalline thin films. As one of the key epitaxial growth technologies, it produces layers that form the basis of many optoelectronic components including mobile phone components (GaAs), semiconductor lasers and LEDs (III-Vs, nitrides), optical communications (oxides), infrared detectors, photovoltaics (II-IV materials), etc. Featuring contributions by an international group of academics and industrialists, this book looks at the fundamentals of MOVPE and the key areas of equipment/safety, precursor chemicals, and growth monitoring. It covers the most important materials from III-V and II-VI compounds to quantum dots and nanowires, including sulfides and selenides and oxides/ceramics. Sections in every chapter of Metalorganic Vapor Phase Epitaxy (MOVPE): Growth, Materials Properties and Applications cover the growth of the particular materials system, the properties of the resultant material, and its applications. The book offers information on arsenides, phosphides, and antimonides; nitrides; lattice-mismatched growth; CdTe, MCT (mercury cadmium telluride); ZnO and related materials; equipment and safety; and more. It also offers a chapter that looks at the future of the technique. Covers, in order, the growth method, material properties, and applications for each material Includes chapters on the fundamentals of MOVPE and the key areas of equipment/safety, precursor chemicals, and growth monitoring Looks at important materials such as III-V and II-VI compounds, quantum dots, and nanowires Provides topical and wide-ranging coverage from well-known authors in the field Part of the Materials for Electronic and Optoelectronic Applications series Metalorganic Vapor Phase Epitaxy (MOVPE): Growth, Materials Properties and Applications is an excellent book for graduate students, researchers in academia and industry, as well as specialist courses at undergraduate/postgraduate level in the area of epitaxial growth (MOVPE/ MOCVD/ MBE).
Download or read book Nanoscale Strontium Titanate Sheets and Crystals written by Jack Andrew Tilka and published by . This book was released on 2018 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: The physical properties of materials are dominated by their structure and composition. Insight into the structure of complex oxide materials has the potential to improve our understanding and eventually control of their physical properties. This PhD thesis reports the development of characterization and fabrication techniques relevant to improving the scientific understanding of complex oxide materials. The work presented here has two components. I report a way to use ideas that were originally developed in semiconductor processing to control the elastic strain state and crystallization process of the model complex oxide SrTiO3. An additional component is an important series of advances in the analysis of diffraction patterns acquired with focused x-ray nanobeams. The fabrication and characterization of nanoscale SrTiO3 has been experimentally shown to allow the introduction of elastic strain into SrTiO3. The creation of thin SrTiO3 crystals from (001)-oriented SrTiO3 bulk single crystals using focused ion beam milling techniques yields sheets with submicron thickness and arbitrary orientation within the (001) plane. Synchrotron x-ray nanodiffraction experiments show that the SrTiO3 sheets have rocking curves with angular widths less than 0.02°. These widths are less than a factor of two larger than bulk SrTiO3, which shows that the sheets are suitable substrates for epitaxial thin film growth. A precisely selected elastic strain can be introduced into the SrTiO3 sheets using a silicon nitride stressor layer. Synchrotron x-ray nanodiffraction studies show that the strain introduced in the SrTiO3 sheets is on the order of 10-4, matching the predictions of an elastic model. This approach to elastic strain sharing in complex oxides allows the strain to be selected within a wide and continuous range of values, an effect not achievable in heteroepitaxy on rigid substrates. An additional fabrication technique is also evaluated here based on the crystallization of SrTiO3 from initially amorphous thin films. This process is known as solid-phase epitaxy in two-dimensional samples but is just beginning to be explored in more complex geometries. I report experiments in both homoepitaxy and heteroepitaxy including measurements of crystal growth rates and the crystallographic orientations of crystals formed in this way. The lateral growth rates are consistent with previously measured vertical growth. This result indicated that previous work on vertical solid-phase epitaxy could be extended into lateral solid-phase epitaxy, which has the power to be applied to complicated non-planar geometries. The highly coherent and tightly focused x-ray beams produced by hard x-ray light sources enable the nanoscale structural characterization of materials but are accompanied by significant challenges in the interpretation of diffraction and scattering patterns. I report here a series of methods that expand the range of physical problems that can be accurately captured by coherent x-ray optical simulations. My approach has been to expand simulations methods to include arbitrary x-ray incident angles and arbitrary epitaxial heterostructures. I first applied these methods to extract the misorientation of lattice planes and the strain of individual layers of Si/SiGe heterostructures relevant to applications in quantum electronics. Further applications reported in this thesis are in probing defects created in the processing of SrTiO3 and in measuring the change in lattice parameter introduced into strained SrTiO3 sheets. The systematic interpretation of nanobeam diffraction patterns aids in the fabrication of SrTiO3 nanostructures.
Download or read book Metal Organic Chemical Vapor Deposition and Atomic Layer Deposition of Strontium Oxide Films on Silicon Surfaces written by Amalia C. Cuadra and published by . This book was released on 2007 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: Epitaxial oxide films like strontium titanate (SrTiO3) grown on silicon have a wide range of potential applications, including high k-dielectric devices, ferroelectrics, optoelectronics, and buffer layers for the heteroepitaxy of III-V semiconductor as well other pervoskites and high-Tc superconductors. The crystalline structure of SrTiO3 consists of alternating sublayers of SrO and TiO2. The epitaxy of SrTiO3 on Si(100) must be initiated with the nucleation of the SrO sublayer first. This thesis presents the methodology used for growing SrO on Si(100) surfaces via metal organic chemical vapor deposition (MOCVD) and atomic layer deposition (ALD). Sr(2,2,6,6-tetramethyl-3,5-heptanedionate) 2 [Sr(thd)2] is the beta-diketonate precursor used to conduct these film growth studies, but the use of this class of metal organic sources comes with several challenges. First, their thermal properties change with atmospheric exposure. Second, successful control of vapor delivery is challenging because beta-diketonates have low vapor pressures and their decomposition temperature is close to their vaporization temperature. Additionally, film growth results are difficult to reproduce because these compounds degrade with time. To overcome these challenges, we developed a Sr(thd)2 delivery scheme using a novel source vaporizer that successfully controls the vaporization and vapor transport to the growth surface under steady vapor pressure while preventing the decomposition of the solid source. This vaporization scheme has been able to grow SrO films on Si(100) with high uniformity and low carbon contamination, as shown with ex-situ Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectroscopy (TOF-SIMS). The MOCVD experiments provided enough evidence to encourage ALD investigations which incorporated the integration of the controlled vaporization with a ultra high vacuum (UHV) reaction chamber that provided the ability to conduct growth experiments on functionalized Si(100) surfaces. The ability to tune the chemistry on the Si(100)-2x1 surface can aid in guiding surface reactions of the metal organic precursor with the growth surface. Our goal has been to hydroxyl terminate the Si(100)-2x1 surface in order to nucleate SrO monolayers. Following the desorption of a protective chemical oxide layer, dissociative chemisorption of H2O is carried out in UHV to hydroxyl terminated Si(100)-2x1. Metal oxide growth can be correlated to the concentration of hydroxyl groups on the silicon surface due to the facilitation of ligand exchange from the surface. Furthermore, hydroxyl-terminated surfaces initiate two-dimensional nucleation of the metal oxide while avoiding incubation periods common to the ALD of metal oxide. In-situ AES and low energy electron diffraction LEED were used to investigate the crystalline quality of the nucleated monolayers and the epitaxial orientation of SrO films on Si(100)-2x1 surfaces. The results of the ALD experiments were, unfortunately, inconsistent. Nonetheless, the focus of this thesis is to show the methodology for developing growth protocols that can be used in ALD reactions on functionalized Si(100)-2x1 surfaces for the epitaxy of metal oxides.
Download or read book Strontium Titanate written by Oleksandr Tkach and published by . This book was released on 2019 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Strontium titanate (STO) is a classical high-permittivity perovskite material known since the 1940s. Although incipient ferroelectric behaviour of SrTiO3 was thoroughly studied during several decades, many new physical phenomena in STO and its solid solutions have been predicted theoretically and observed experimentally in past few years. The obtained results were successfully applied for the development of modern electronic devices on the basis of macroscopic and nanostructured samples. Besides the incipient ferroelectricity, properties of STO include a structural phase transition, semiconductivity, superconductivity, and thermoelectricity, among others. This book provides the latest information on the developments of field preparation, characterization, and application of STO and the materials based on it, with perspectives on future research. It collects the contributions of several established researchers from around the world on the fundamental mechanisms, processing, and possible uses for STO-based materials in the form of single crystals, thin films, and ceramics. This book covers a broad range of topics related to STO and materials based on it, including an overview of lattice dynamics and magnetic resonance characterization, Sr/Ti ratio, and stress induced modification of the properties, modelling, and simulation of improper ferroelectricity and multiferroic phases, dielectric responses and thermoelectric performance for tunable devices, and energy harvesting applications, respectively.
Download or read book Structural and Optical Properties of Strontium Titanate Thin Films Prepared by Spray Pyrolysis written by Siti Aisah Mat and published by . This book was released on 2014 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Defects and Magnetic Properties of Iron implanted Strontium Titanate and Thin Fims i e Films written by Misha Chavarha and published by . This book was released on 2012 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Physical vapor deposition was used to grow good quality crystalline stoichiometric SrTiO3 thin films on Si(001) substrates using a systematic approach starting from an understanding of the kinetics and thermodynamics of the system and finishing with the development of a procedure for preparing high quality SrTiO3/Si interface. Growth of optimized SrTiO3 perovskite structures on Si requires careful transformation of a thin interfacial SrSix layer into the initial SrTiO3 lattice cells. The critical aspects of the growth, such as low temperature and low oxidant partial pressure, are identified. Crystallinity and stoichiometry of SrTiO3 were verified using powder x-ray diffraction (XRD) and Rutherford backscattering spectroscopy (RBS). The SrTiO3/Si(001) interface was examined with X-ray photoemission spectroscopy (XPS) and RBS. The optimum composition can be represented with low concentration (thickness) of strontium silicate phases at the interface (SrxSiyOy) as well as a strong signal from strontium titanate peaks. Thicker samples were grown with the procedure developed and were implanted with iron at 2 ́1016 ions/cm2 for future magnetic characterization. In parallel to the thin film growth, (001) SrTiO3 single crystals were implanted with iron at doses ranging from 2 ́1014 to 2 ́1016 ions/cm2 and magnetic measurements were carried out with a superconducting quantum interference device (SQUID). The results show negative susceptibility, predominately diamagnetic behavior which is characteristic of SrTiO3 and small paramagnetic response at low magnetic fields, indicating the possible presence of oxygen/titanium vacancies. The temperature dependence of magnetization measurements did not reveal phase changes. We note that it was difficult to identify any trends between implanted samples most likely due to oxygen contamination of the measurement system. Future experiments are proposed to develop a quantitative and consistent agreement between Fe phases in SrTiO3, SrTiO3 defect concentrations and magnetic responses.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1997 with total page 940 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Growth of Strontium Titanate and Lutetium Ferrite Thin Films by Molecular beam Epitaxy written by Charles M. Brooks and published by . This book was released on 2012 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Crystal Structure on Strontium Titanate Thin Films and Their Dielectric Properties written by Satreerat Kampangkeaw and published by . This book was released on 2004 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microstructure and Nonstoichiometry of Barium Strontium Titanate Thin Films for Dram Applications written by and published by . This book was released on 1999 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper we investigate the microstructural accommodation of nonstoichiometry in (Ba(subscript x)Sr{sub 1-x}Ti{sub 1+y}O{sub 3+z}) thin films grown by chemical vapor deposition. Films with three different (Ba+Sr)/Ti ratios of 49/51 (y=0.04 in the notation of the formula above), of 48/52 (y=0.08) and of 46.5/53.5 (y=O.15), were studied. High-resolution electron microscopy is used to study the microstructure of the BST films. High-spatial resolution electron energy-loss spectroscopy (EELS) is used to reveal changes in chemistry and local atomic environment both at grain boundaries and within grains as a function of titanium excess. We find an amorphous phase at the grain boundaries and grain boundary segregation of excess titanium in the samples with y=0.15. In addition, EELS is also used to show that excess titanium is being partially accommodated in the grain interior. Implications for the film electrical and dielectric properties are outlined.
Download or read book Electrical and Optical Characterization of Defects in Strontium Titanate Thin Films Grown by Organometallic Chemical Vapor Deposition written by William Allen Feil and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 2240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transport Properties and Superconductivity of Lanthanum doped Strontium Titanate Thin Films Grown by Laser Ablation written by David Olaya and published by . This book was released on 2003 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Off Axis Growth of Strontium Titanate Films with High Dielectric Constant Tuning and Low Loss written by Satreerat Kampangkeaw and published by . This book was released on 2003 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have measured the nonlinear dielectric properties of strontium titanate (STO) thin films grown on neodymium gallate (NGO) and lanthanum aluminate (LAO) substrates. The films prepared by off-axis pulsed laser deposition were characterized by their dielectric constant and loss tangent at 1 MHz and 2 GHz, and from room temperature down to 4 K. The resulting films show significant variations of dielectric properties with position of the substrates with respect to the plume axis. STO films on LAO substrates show low loss and high dielectric constant in regions near the plume axis. On the other hand, STO on NGO shows this effect only on the films grown far from the plume axis. We also obtained a figure of merit from the relative variation of the dielectric constant divided by the loss tangent in the presence of a DC electric field up to +/- 4 V/micrometers. Careful mapping of the plume crossection allowed us to improve the quality and reproducibility of the dielectric films, obtaining a best figure of merit at 2 GHz and 4 K close to 100 for NGO substrate but only well off axis.
Download or read book Phase Transformations in Textured Strontium Titanate Thin Films on Epitaxial Platinum Bottom Electrodes written by Sean Patrick Keane and published by . This book was released on 2006 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Growth and Characterization of Barium Strontium Titanate Thin Films with Enhanced Electrical Properties Using Pulsed Laser Deposition written by Anuranjan Srivastava and published by . This book was released on 1999 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
