Download or read book The Surface Chemistry of Si 111 7x7 written by Marc Michael Kollrack and published by . This book was released on 1990 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Surface Chemistry of Si 111 7 Times 7 Reactions with Co and with Small Organic Molecules written by M.M. Kollrack and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Surface Chemistry of Aromatic Molecules on the Silicon 111 7x7 Surface written by Yong Cao and published by . This book was released on 2000 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Surface Chemistry of Silicon The Behavior of Dangling Bonds written by J. T Yates (Jr) and published by . This book was released on 1991 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The role of surface dangling bonds in controlling the surface chemistry of Si(100) and Si(111) has been investigated using surface science methods. The adsorption and decomposition of acetylene on Si(100) has been shown to occur by means of mobile precursor mechanism, leading to a di-sigma chemisorbed ethylenic species occupying Si dimer sites on Si(100). This species decomposes at elevated temperatures to produce adsorbed carbon and hydrogen (800 K) and then silicon carbide (1000 K). The activity of Si(111) for the adsorption of species such as ammonia and atomic hydrogen can be significantly reduced by doping of the surface region with boron. It has been shown that subsurface boron significantly changes the structure of Si(111)-(7x7) to a (sq rt 3 x sq rt 3) R 30 deg structure. In addition, the local doping of the surface reduces the chemical activity of the dangling bonds so that neither the dissociation of NH3 nor the adsorption of atomic hydrogen will occur.

Download or read book Surface Chemistry of Acetonitrile Acrylonitrile and N methylpyrrole on SI 111 7x7 written by Xianfeng Chen and published by . This book was released on 2001 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book PH3 Surface Chemistry on Si 111 7x7 A Study by Auger Spectroscopy and Electron Stimulated Desorption Methods written by R. M. Wallace and published by . This book was released on 1990 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: The adsorption and decomposition of phosphine hydride on silicon (III)-(7x7) was investigated in ultrahigh vacuum by means of temperature programmed desorption (TPD), low-energy electron diffraction (LEED), Auger electron spectroscopy (AES) and electron stimulated desorption (ESD) methods. Phosphine adsorbs on Si(III)-(7x7) at T=120K with an initial sticking coefficient of S(o) equivalent to 1 through a mobile (extrinsic) precursor state. Some PH3 dissociative adsorption at 120 K is observed. Thermal activation of the adsorbed species results in desorption of a molecular PH3 species up to 550 K. Further heating produces H2(g) desorption at T equivalent to 740 K and P2(g) desorption at T equivalent to 1010 K, thus indicating that PH3 decomposition has occurred. AES and ESD studies of the adsorbed species reveal that decomposition takes place by the breaking of P-H bonds in PHx(a) to form Si-H species on the surface for 120 K

Download or read book The Elucidation of the Mechanism of the Initial Stages of Si 111 7x7 Oxidation Using Scanning Tunneling Microscopy written by Ph Avouris and published by . This book was released on 1992 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The capability of the scanning tunneling microscopy (STM) and spectroscopy (STS) to probe the topography and electronic structure of surfaces and adsorbate layers with atomic resoLution makes it a powerful took in the study of surface chemistry. Here we use STM, STS, ultraviolet photoemission spectroscopy (LIPS) and electronic structure calculations to study the long-standing problem involving the nature of the initial stages of the oxidation of silicon. There have been a large number of studies on this issue utilizing a great variety of techniques. However, not only is the mechanism of oxidation still unclear, but there is not even agreement on what kind of product(s) is formed. Several different configurations have been proposed for the oxygen-containing sites in the early stages of the reaction. They involve oxygen atoms saturating the dangling-bonds of top-layer Si atoms, oxygen atoms inserted in back-bonds but leaving the dangling-bonds intact, or molecular forms of oxygen attached to surface atoms or bridging two surface Si atoms.

Download or read book Site Specific Surface Chemistry of Prototypical Amino Acid Peptide and DNA Base Groups on Si 111 7x7 written by Avisek Chatterjee and published by . This book was released on 2012 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: The surface chemistry of glycine, glycylglycine, adenine and thymine on Si(111)7x7 are studied for the first time by X-ray photoelectron spectroscopy (XPS) and Scanning Tunneling Microscopy (STM) experimental techniques. The results are supported with the density functional theory based computations by elucidating equilibrium geometries of the adsorbate-substrate structures. In contrast to common carboxylic acids, glycine is found to adsorb on Si(111)7x7 dissociatively through cleavage of a NH bond instead of O-H bond. Increasing the glycine film thickness reveals the existence of a transitional adlayer between the first adlayer and the zwitterionic multilayer. This transitional adlayer is estimated to be 1-2 adlayer thick and is characterized by the presence of intermolecular NxxxHO hydrogen bond. Density Functional Theory (DFT) calculations of glycine adsorption on Si(111)7x7 and Si(100)2x1 model surfaces illustrates that the formation of different surface adducts involving the -NH2 and -COOH functional groups plays a vital role in determining the adsorbate structures on the 7x7 and 2x1 surfaces and therefore control the ultimate surface adproducts. The unique unidentate adsorption configuration of glycine on Si(111)7'7 through NH dissociation, with the unreacted carboxyl group remaining free, has shown to be an effective way to capture other biomolecules such as glycylglycine, alanine, adenine and thymine on a glycine-functionalized Si(111)7x7 surface and through [OHxxxN] hydrogen bonding. The captured molecules can be released simply by annealing. The glycine-functionalized Si(111) surface therefore provides a flexible platform for potential applications as selective molecular traps, chemical sensors, and biomolecular electronic components. The STM study of glycine adsorption on Si(111)7x7 provides strong evidence for dissociative adsorption of glycine through N-H bond cleavage (and N-Si bond formation) as reported in X-ray photoemission study. In addition, STM images with higher glycine exposures shows that the second adlayer is mediated by vertical hydrogen bonding and that the horizontal hydrogen bonding between two N-H dissociated glycine adsorbates at two neighbouring adatom sites can be possible. Similar to glycine adsorption on Si(111)7x7 surface, the XPS investigation of glycylglycine on the Si(111)7x7 also reveals three growth stages; dissociative adsorption of glycylglycine in the first adlayer, a hydrogen bonded transitional adlayer and a ultimately the zwitterionic multilayer. In contrast to glycine, glycylglycine adsorbs in a bidentate fashion with the dissociation of N-H and O-H bonds in the first adlayer. The STM investigations support the evidence of dissociative adsorption of glycylglycine in a bidentate fashion on two adjacent Si adatoms across a dimer wall or an adatom-restatom pair as observed from the filled state images. The strong bidentate interactions of glycylglycine with the Si atoms also inhibit surface diffusion of the adsorbed fragment, and the adsorption apparently follows random sequential adsorption statistics. The XPS and STM results of the glycylglycine adsorption on Si(111)7x7 can be corroborated with our DFT based computational study which suggests that the bidentate adproducts involving N-H and O-H dissociations are viable. In addition, the DFT results also predict that the free -CONH- and -COOH groups remaining on the respective bidentate adstructures could facilitate adsorption of the second adlayer through the formation of hydrogen bonding. In sharp contrast to glycine and glycylglycine, the STM studies of adenine on Si(111)7x7 shows the evidence of molecular adsorption of adenine through dative bonding to the surface silicon atoms. The majority of the adsorbed adenine molecules are found to appear as dimer pairs at the initial adsorption stage, which are formed by hydrogen bonds. The experimental evidence of the formation of dative bonds between the substrate and adenine and the feasibility of the H-bond mediated dimers can also be supported by ab-initio DFT/B3LYP/6-31Gxx(d, p) calculations and X-ray photoemission data. As the exposure of adenine increases, the numbers of dimers as well as the unique self-organized adenine structures also increase. These dimers and self-assembled structures are found to be most prominent in the growth of adenine nanowires, most notably aligned along the Si dimer-wall or [-110] direction of the 7x7 unit cell. The self-aligned adenine dimer nanowires offer a natural template for catch-and-release biosensing, lithography, and molecular electronic applications. On the other hand, the STM study of another nucleobase thymine on Si(111)7x7 surfaces reveal the existence of three different kinds of adsorption products. When compared with the XPS and DFT based computational methods, it can be suggested that the three different adsorption products could correspond to 1,4 and 3,6 cycloaddition products and hydrogen bonded adcomplex respectively. The statistical analysis for three different exposures of Thy on the 7x7 surface further helps to assign the three different features observed in STM images to the 1,4 and 3,6 cycloaddition products as well as to the hydrogen bonded adcomplexes. The present work therefore illustrates the importance of the unique site specific surface chemistry of these four prototypical biomolecules on Si(111)7x7 which could be harnessed and used in the future biodevices by functionalizing the Si(111)7x7 surface with appropriate molecules such as glycine, glycylglycine, adenine or thymine.

Download or read book Group IV Semiconductor Surface Chemistry written by Guang-Quan Lu and published by . This book was released on 1992 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Surface Chemistry of Silicon and Germanium Molecular Precursors for Epitaxy on Silicon written by Peter Alan Coon and published by . This book was released on 1992 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Studies of Surface Reaction Kinetics on Si 111 7x7 Using Laser induced Thermal Desorption written by Birgit Gundala Koehler and published by . This book was released on 1990 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Jewels written by and published by . This book was released on 1974 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Atomic and Molecular Manipulation written by Andrew J. Mayne and published by Elsevier. This book was released on 2011-09-02 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Work with individual atoms and molecules aims to demonstrate that miniaturized electronic, optical, magnetic, and mechanical devices can operate ultimately even at the level of a single atom or molecule. As such, atomic and molecular manipulation has played an emblematic role in the development of the field of nanoscience. New methods based on the use of the scanning tunnelling microscope (STM) have been developed to characterize and manipulate all the degrees of freedom of individual atoms and molecules with an unprecedented precision. In the meantime, new concepts have emerged to design molecules and substrates having specific optical, mechanical and electronic functions, thus opening the way to the fabrication of real nano-machines. Manipulation of individual atoms and molecules has also opened up completely new areas of research and knowledge, raising fundamental questions of "Optics at the atomic scale", "Mechanics at the atomic scale", Electronics at the atomic scale", "Quantum physics at the atomic scale", and "Chemistry at the atomic scale". This book aims to illustrate the main aspects of this ongoing scientific adventure and to anticipate the major challenges for the future in "Atomic and molecular manipulation" from fundamental knowledge to the fabrication of atomic-scale devices. Provides a broad overview of the field to aid those new and entering into this research area Presents a review of the historical development and evolution of the field Offers a clear personalized view of current scanning probe microscopy research from world experts

Download or read book Fundamental Aspects of Ultrathin Dielectrics on Si based Devices written by Eric Garfunkel and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 503 pages. Available in PDF, EPUB and Kindle. Book excerpt: An extrapolation of ULSI scaling trends indicates that minimum feature sizes below 0.1 mu and gate thicknesses of Audience: Both expert scientists and engineers who wish to keep up with cutting edge research, and new students who wish to learn more about the exciting basic research issues relevant to next-generation device technology.

Download or read book Computations for the Nano Scale written by P.E. Blöchl and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Research Workshop, Aspet, France, October 12-16, 1992

Download or read book Physics Of Semiconductors Proceedings Of The 20th International Conference In 3 Volumes written by E M Anastassakis and published by World Scientific. This book was released on 1990-11-29 with total page 2768 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gathering top experts in the field, the 20th ICPS proceedings reviews the progress in all aspects of semiconductor physics. The proceedings will include state-of-the-art lectures with special emphasis on exciting new developments. It should serve as excellent material for researchers in this and related fields.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt: