Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"Dangling bond"”.
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Density Functional Study of Hydrogen in Amorphous Silicon
… energetics for H to move from a variety of Si-H bonds to the bulk chemical potential. For isolated Si-H bonds (i.e. in micro-cavities without any bond reconstruction) the energetics are not consistent with observations. However, if the remaining Si reconstructs with a nearby silicon creating a …
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Crystallization of Isolated Amorphous Zones in Semiconductors
… by an electronic excitation which creates a dangling bond pair. By migrating along the crystalline/amorphous interface these dangling bonds are capable of reconstructing to the crystal a large number of atoms through a mechanism similar to that for thermally activated solid phase epitaxial …
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The Electronic Structure and Reactivity of Sulfide Surfaces: Combining Atomic-Scale Observations with Theoretical Calculations
… that this band is comprised primarily of non-bonding Fe 3d t<sub>2g</sub> and lesser S 3p and Fe 3d e<sub>g</sub> states. Ab-initio slab calculations predict that the broken bonding symmetry at the surface displaces a Fe 3d<sub>Z</sub>2 dangling bond state into the bulk band gap. Evidence …
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Interfacial Structures of Oxides on GaAs
… proposed as the key factor to solve the surface dangling bond problem. X-ray photoelectron spectroscopy (XPS) and Auger data show that Gd rich in the interface region is the essential part of the good quality MOS devices. It suggest that carefully controlled the initial growth conditions such as …
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Quantum dynamical study of Si(100) surface-mounted, STM-driven switches at the atomic and molecular scale
… the switching of single H-atoms between two dangling-bond chemisorption sites on a Si-dimer of the Si(100) surface (Grey et al., 1996). The second system examines the conformational switching of single 1,5-cyclooctadiene molecules chemisorbed on the Si(100) surface (Nacci et al., 2008). The …
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Charge-carrier transport in amorphous organic semiconductors
… by van der Waals forces rather than covalent bonds. Van der Waals bonding eliminates the danger of dangling bond traps in amorphous or polycrystalline inorganic films, but results in narrower electronic bandwidths. Combined with spatial and energetic disorder due to weak intermolecular …
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Silicon-Based Molecular Nanotechnology: Fabrication and Characterization With the Scanning Tunneling Microscope
… from the Si(100)-2x1:H surface. The remaining dangling bond patterns serve as atomically precise templates upon which other materials can spontaneously self-assemble. By utilizing this selective chemistry in situ, several organic molecules (e.g., norbornadiene (NBE), copper phthalocyanine …
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Scanning tunneling microscopy and spectroscopy of nanometer scale metallic features on silicon surfaces
… features are studied. First, an unpaired dangling bond (DB) can be formed on Si(100)-2×1:H surface using an STM nanolithography method. The unpaired DB, which shows metallic behavior, can perturb its surroundings electronically up to ~1.9 nm by introducing a near-midgap state in the local …
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Photoconductivity in amorphous silicon
… states was of a value expected for the neutral dangling bond, so they have been denoted as D states. States outside this energy were seen to be ineffective as recombination centres. The model thus has features intermediate between a simple 2-trap system and a distributed density of states. …
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Steady state and transient photoconductivity in n-type amorphous silicon
… which the recombination centres are exclusively dangling bond defects mainly in the D state. The band tail states trap most of the charge, act as carrier reservoirs and manifest themselves only in the charge neutrality relation. The recombination rate limiting step is hole release and subsequent …
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Advanced materials, process, and designs for silicon photonic integration
… a-Si, we adapt hydrogen passivation to reduce dangling bond density.
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The interaction of xenon difluoride with Si(100)
… with high probability solely on the Si dangling bonds up to a coverage of about one monolayer (ML). Molecular fluorine has previously been observed to react similarly, saturating the dangling bonds at 1 ML coverage. The thermal desorption products and kinetics from the fluorinated layer …
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The chemical dynamics of XeF₂ and Xe(F₂) reactions with Si(100)
… atom abstraction mechanism, whereby a surface dangling bond abstracts a F atom from the incident molecule, scattering the complementary F atom or XeF fragment into the gas phase. However, once all dangling bonds are fluorinated and a coverage of 1 ML F is attained, the chemistry of these two …
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Study of Si/SiO2 interface passivation and SiO2 reliability on deuterium implanted silicon
… interface states in the silicon band gap is the dangling bond, which degrades performance of MOS devices. Passivation of these bonds with hydrogen had been found to diminish their effect but the improvement degrades the operation due to hot electron effect. Passivation with deuterium annealing …
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Influence of bulk defects in p-type Czochralski silicon on reliability of high efficiency solar cells
… time, the defect responsible for LeTID is a Si dangling bond within a vacancy agglomerate and hydrogen in the vicinity. We postulate that LeTID can be suppressed with slower pulling rates of the Czochralski Si and/or an optimized contact firing process. We extend our work to solar cells to …
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Design principles for high performance, low environmental impact silicon cleans
… correspond to the three physical states of a dangling bond. The doublyoccupied state may play a role in native oxide growth and metal deposition; the unoccupied state is a likely site for attack during fluoride etching. Metal contaminants at the silicon-liquid interface have also been studied …
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Density Functional Simulations of Defect Behavior in Oxides for Applications in MOSFET and Resistive Memory
… Ge, which is well explained by the interfacial dangling bond states. These results are important to tune Schottky barrier heights (SBHs) for n-type contacts on Ge for use on Ge high mobility substrates in future CMOS devices. In chapter 6, we investigate the surface and subsurface O vacancy …
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Binding and diffusion of a silicon adatom on silicon (001) surface: An atomic scale simulation
… single-layer steps, namely type A (S$\rm\sb A$), bonded type B (S$\rm\sb B$) and nonbonded type B (S$\rm\sb{B\sp\prime}$), on Si(001) have been studied, using a modified empirical and first-principle methods. The results presented in this thesis, providing the atomistic scale details of the …
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The role of lattice excitation in Si etching
… an atom abstraction mechanism, where a surface dangling bond abstracts a F atom from the incident molecule, scattering the F atom or XeF fragment into the gas phase. Past 1 ML coverage, further exposure to F₂ results in no increase in F coverage, indicating that reaction of F₂ with the …
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Computer modelling and experimental characterisation of amorphous semiconductor thin films and devices
… reason for this is that the sensitivity of the dangling bond density on the Fermi-level position is overestimated giving an excessively high defect density near the doped layers, with the result that the modelled performance of the <i>p-i-n</i> diode is much poorer than for actual devices. A …