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Oxide Interfaces (oxide + interface)
Selected AbstractsActive Metal Electrode,Oxide Interface in Gas Sensor Operation Probed by In Situ and Time-Resolved X-Ray SpectroscopyCHEMPHYSCHEM, Issue 1 2010Aleksander Gurlo Dr. The feasibility of the in situ and operando methodology in studying the chemical and electronic phenomena associated with an active metal electrode,oxide interface in metal-oxide-based gas sensors (picture) is demonstrated. It is experimentally verified that the Pt electrodes in metal-oxide based gas sensors are partially oxidised and that the oxidised Pt electrodes contribute to overall sensing performance. [source] Complex Oxide Interfaces: Determination of Electronic Structure of Oxide,Oxide Interfaces by Photoemission Spectroscopy (Adv. Mater.ADVANCED MATERIALS, Issue 26-27 201027/2010) Precise understanding of structure , property relationships at interfaces is critical for electronic devices, particularly at the nanometer scale, and can be achieved by a synergy of high-quality growth, advanced characterization, and first principles theory (on page 2950). [source] Direct Evidence for Cation Non-Stoichiometry and Cottrell Atmospheres Around Dislocation Cores in Functional Oxide InterfacesADVANCED MATERIALS, Issue 22 2010Miryam Arredondo Long-range strain fields associated with dislocation cores at an oxide interface are shown to be sufficient enough to create significant variations in the chemical composition around the core (Cottrell atmospheres). Such stress-assisted diffusion of cations towards the cores is proposed to significantly impact the properties of nanoscale functional devices. The figure shows a Z-contrast image of a single dislocation core at an oxide interface. [source] Second harmonic generation spectroscopy on Si surfaces and interfacesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 8 2010Kjeld Pedersen Abstract Optical second harmonic generation (SHG) spectroscopy studies of Si(111) surfaces and interfaces are reviewed for two types of systems: (1) clean 7,×,7 and -Ag reconstructed surfaces prepared under ultra-high vacuum conditions where surface states are excited and (2) interfaces in silicon-on-insulator (SOI) structures and thin metal films on Si surfaces where several interfaces contribute to the SHG. In all the systems resonances are seen at interband transitions near the bulk critical points E1 and E2. On the clean surfaces a number of resonances appear below the onset of bulk-like interband transitions that can be referred to excitations of dangling bond surface states. Adsorption of oxygen leads to formation of a new surface resonance. Such resonances appearing in the region between the bulk critical points E1 and E2 are also shown to be important for Si/oxide interfaces in SOI structures. Finally, examples of spectroscopy on layers buried below thin Ag and Au films are given. [source] Direct Evidence for Cation Non-Stoichiometry and Cottrell Atmospheres Around Dislocation Cores in Functional Oxide InterfacesADVANCED MATERIALS, Issue 22 2010Miryam Arredondo Long-range strain fields associated with dislocation cores at an oxide interface are shown to be sufficient enough to create significant variations in the chemical composition around the core (Cottrell atmospheres). Such stress-assisted diffusion of cations towards the cores is proposed to significantly impact the properties of nanoscale functional devices. The figure shows a Z-contrast image of a single dislocation core at an oxide interface. [source] Ambient and temperature dependent electric properties of backgate graphene transistorsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 4 2010Christian Hummel Abstract The electrical behavior of backgate graphene field effect (GFET) transistor was studied at different ambient conditions. Backgate p-channel GFET transistors were fabricated on oxidized silicon wafers by exfoliation of graphite. The carrier mobilities were determined from the measured transconductance. For all ambients investigated (N2, Ar, and air), the graphene transistors show enhanced mobilities at elevated temperatures. This behavior can be explained by a stronger screening of scattering centers, i.e., defects in graphene and at the graphene oxide interface, with increasing temperature. For operation in air the transistors showed a higher transconductance compared to the operation in nitrogen and argon due to the strong acceptor-like behavior of gases adsorbed on the graphene surface. Effect of temperature and ambient on the output characteristic of a backgate GFET. [source] Active Metal Electrode,Oxide Interface in Gas Sensor Operation Probed by In Situ and Time-Resolved X-Ray SpectroscopyCHEMPHYSCHEM, Issue 1 2010Aleksander Gurlo Dr. The feasibility of the in situ and operando methodology in studying the chemical and electronic phenomena associated with an active metal electrode,oxide interface in metal-oxide-based gas sensors (picture) is demonstrated. It is experimentally verified that the Pt electrodes in metal-oxide based gas sensors are partially oxidised and that the oxidised Pt electrodes contribute to overall sensing performance. [source] Band alignment at metal,semiconductor and metal,oxide interfacesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 2 2010John Robertson Abstract The mechanisms of Schottky barrier formation are reviewed from the metal-induced gap state model to the universal defect model, and the chemical reaction model. The recent progress in understanding barrier heights and band offsets in Si , high dielectric constant oxide and metal high dielectric constant oxide systems is then discussed, and interesting they contain components of each model. The greater emphasis on understanding defect reactions has allowed us to separate the effects of intrinsic mechanisms, metal induced gap states (MIGS) and extrinsic mechanisms (defects). [source] A hybrid functional scheme for defect levels and band alignments at semiconductor,oxide interfacesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 2 2010Peter Broqvist Abstract We introduce a theoretical scheme to study defect energy levels and band alignments at semiconductor,oxide interfaces. The scheme relies on hybrid functionals to overcome the band gap underestimation typically achieved with semilocal density functionals. For atomically localized defects, the more accurate description achieved with hybrid functionals does not lead to significant shifts of the charge transition levels, provided these levels are referred to a common reference potential. This result effectively decouples the shifts of the band edges with respect to the defect levels. We also show that relative shifts of conduction and valence band edges as determined by exact nonlocal exchange lead to band offsets in excellent agreement with experimental values for several semiconductor,oxide interfaces. The proposed scheme is illustrated through a series of applications, including the dangling bond defects in silicon and germanium, the charge state of the O2 molecule during silicon oxidation, and the oxygen vacancy in Si,SiO2,HfO2 stacks. [source] SHORT COMMUNICATION: Surface passivation by rehydrogenation of silicon-nitride-coated silicon wafersPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 3 2005Michelle McCann Abstract A silicon wafer with a silicon nitride layer deposited by low pressure chemical vapour deposition may be subjected to high-temperature treatments without adversely affecting the electronic properties of the silicon on the condition that a thin oxide is present under the nitride. After high-temperature treatments there is an apparent degradation in effective lifetime, probably due to a loss of hydrogen from the silicon/oxide interface. Effective lifetimes can be completely recovered by thermal treatment in a hydrogen-containing ambient. This work has useful applications for solar cells as many of the properties of these nitrides can be used to advantage. Copyright © 2004 John Wiley & Sons, Ltd. [source] | ||||||||||