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InGaSb-on-insulator (InGaSb-OI) and InAs/InGaAs/InAs-on-insulator (InAs/InGaAs-OI) structures have been realized on Si by a direct wafer bonding (DWB) technology using atomic-layer-deposition Al2O3. While strain introduced in InGaSb channel layers grown on InAs can enhance the hole mobility of the Sb-based channel layers, a difficult issue of fabricating InGaSb-OI wafers is to obtain a smooth InGaSb surface, which is mandatory for wafer bonding. In this study, the surface of a 20-nm-thick In0.185Ga0.815Sb channel grown on an InAs (100) substrate and an InAs (2.5 nm)/In0.185Ga0.815Sb (20 nm)/InAs (2.5 nm) channel with a 20-nm-thick GaSb buffer layer grown on an InAs (100) substrate by metal-organic chemical vapor deposition have a root mean square of the surface roughness as low as 0.16 and 0.22 nm, respectively, over a scan area of 10 × 10 μm2, which are smooth enough to employ the wafer bonding. As a result, the fabrication of the InGaSb-OI wafers by the DWB and the operation of InGaSb-OI p-channel metal-oxide-semiconductor field-effect transistors (p-MOSFETs) by using the DWB wafers are demonstrated. Also, the performance of InGaSb-OI p-MOSFETs is found to be improved by inserting ultrathin InAs layers between InGaSb and insulating buried oxide layers. An InGaSb-OI and an InAs/InGaAs-OI p-MOSFET under the accumulation-mode operation exhibit a peak mobility of ∼161 and ∼273 cm2/V s, respectively. The channel hole mobility of the InGaSb-OI p-MOSFET is higher than that of the GaSb-on-insulator (GaSb-OI) p-MOSFET and can exceed that of Si p-MOSFETs. [ABSTRACT FROM AUTHOR]

A non-saturating linear magnetoresistance (MR) is observed in Sb2SeTe2 topological insulator. The results show that the MR slope and the critical magnetic field of the linear MR are proportional to the carrier mobility and inverse mobility, respectively. These are consistent with the prediction of a model, which is constructed by Parish and Littlewood [Nature 426, 162 (2003)], in the weak mobility fluctuation condition. The Kohler plot of the magnetoresistance does not collapse onto a single curve that supports the multi-carriers scattering mechanisms. [ABSTRACT FROM AUTHOR]

Bi2Te3 and Bi2Se3 are well known 3D-topological insulators (TI). Films made of these materials exhibit metal-like surface states with a Dirac dispersion and possess high mobility. The high mobility metal-like surface states can serve as building blocks for a variety of applications that involve tuning their dispersion relationship and opening a band gap. A band gap can be opened either by breaking time reversal symmetry, the proximity effect of a superconductor or ferromagnet or adjusting the dimensionality of the TI material. In this work, methods that can be employed to easily open a band gap for the TI surface states are assessed. Two approaches are described: (1) Coating the surface states with a ferromagnet which has a controllable magnetization axis. The magnetization strength of the ferromagnet is incorporated as an exchange interaction term in the Hamiltonian. (2) An s-wave superconductor, because of the proximity effect, when coupled to a 3D-TI opens a band gap on the surface. Finally, the hybridization of the surface Dirac cones can be controlled by reducing the thickness of the topological insulator film. It is shown that this alters the band gap significantly. [ABSTRACT FROM AUTHOR]

New technique of acoustic spectroscopy to study interface states in metal-oxide-semiconductor (MOS) structures with a very thin oxide layer based on the acoustoelectric effect resulting from the interaction between the longitudinal acoustic wave and semiconductor-insulator interface is presented. The essential principles and theoretical background of this acoustic spectroscopy technique that can determine the interface states distribution from the measured acoustoelectric response signal as a function of gate voltage (Uac-Ug characteristics) are described. The results obtained on the representative set of MOS structures prepared on both n- and p-type Si substrates by nitric acid oxidation of Si technology and undergone also some thermal treatment demonstrate that the introduced technique of acoustic spectroscopy can be a very useful tool for the interface states characterization. [ABSTRACT FROM AUTHOR]

Correct measurement of the power of a continuous wave signal superimposed on a broadband noise is a presupposition for the accuracy of the gain saturation measurement of a superconductor-insulator-superconductor mixer. In practice, the response of a logarithmic power detector to a mixture of broadband noise and continuous wave signal can be unexpectedly nonlinear. This nonlinearity can cause significant error if correction is not applied. [ABSTRACT FROM AUTHOR]

A high current density of 1 kA/cm2 is experimentally realized in enhancement-mode Ga2O3 vertical power metal-insulator field-effect transistors with fin-shaped channels. Comparative analysis shows that the more than doubled current density over the prior art arises from a larger transistor channel width; on the other hand, a wider channel also leads to a more severe drain-induced barrier lowering therefore premature transistor breakdown at zero gate-source bias. The observation of a higher current density in a wider channel confirms that charge trapping in the gate dielectric limits the effective field-effect mobility in these transistor channels, which is about 2× smaller than the electron mobility in the Ga2O3 drift layer. The tradeoff between output-current density and breakdown voltage also depends on the trap density. With minimal trap states, the output current density should remain high while breakdown voltage increases with decreasing fin-channel width. [ABSTRACT FROM AUTHOR]

This work focuses on the experimental study of the conductivity and the permittivity of ZnO-P2O5/Co (ZP/Co) composites as function of frequency in the range of 100-106 Hz at room temperature. The conductivity evolution shows a high percolating jump from low to high loaded ZP matrix with Co filler, indicating an insulator-semiconductor phase transition. Above the percolation threshold, the obtained conductivity is between 10−1 and 10° S/cm and is frequency independent. While, for low filler volume fraction, it is frequency dependent and it is about 10−8 S/cm at 100 Hz. Moreover, it should be noticed that around the percolation threshold, a significant value of dielectric constant about 105 was observed at room temperature and low frequency 100 Hz. Furthermore, the distribution of the relaxation processes was also investigated below the percolation threshold. Indeed, a relaxation peak about 106 rad/s in the curves of electric modulus M″(ω) was observed. It is successively described by Davidson-Cole model and an account of the interpretation of obtained results is given. [ABSTRACT FROM AUTHOR]

In this paper, we report the study of transport and magnetic properties of ytterbium hexaboride (YbB 6 ) nanowires grown by a low trigger-temperature (200–240 °C) solid state method. The temperature dependence of resistivity shows that the YbB 6 nanowire undergoes a semiconductor-insulator transition (SIT) below 20 K with an activation energy Δ E of 1 meV. The value of ρ at 2 K reaches 49 times the value of ρ at 300 K ( ρ 2 K / ρ 300 K = 49). The observed non-saturating magnetoresistance (MR) has a linear relationship with B 2 . The anomalous electronic transport in the YbB 6 nanowire can be explained by the mixed valence of Yb ions due to the boron deficiency supporting by the X-ray photoelectron spectroscopy (XPS) and paramagnetic magnetization. [ABSTRACT FROM AUTHOR]

The charge carrier transport mechanism of passivating contacts which feature an ultra-thin oxide layer is investigated by studying temperature-dependent current-voltage characteristics. 4-Terminal dark J-V measurements at low temperatures reveal non-linear J-V characteristics of passivating contacts with a homogeneously grown silicon oxide, which result in an exponential increase in contact resistance towards lower temperature. The attempt to describe the R(T) characteristic solely by thermionic emission of charge carriers across an energy barrier leads to a significant underestimation of the resistance by several orders of magnitude. However, the data can be described properly with the metal-insulator-semiconductor (MIS) theory if tunneling of charge carriers through the silicon oxide layer is taken into account. Furthermore, temperature-dependent light J-V characteristics of solar cells featuring passivating contacts at the rear revealed a FF drop at T < 205 K, which is near the onset temperature of the exponential increase in contact resistivity. [ABSTRACT FROM AUTHOR]

A new method for analytical applications based on the Maxwell-Wagner effect is proposed. Considering the interaction of carbonaceous materials with an electromagnetic field in the microwave frequency range, a very fast heating is observed due to interfacial polarization that results in localized microplasma formation. Such effect was evaluated in this work using a monomode microwave system, and temperature was recorded using an infrared camera. For analytical applications, a closed reactor under oxygen pressure was evaluated. The combination of high temperature and oxidant atmosphere resulted in a very effective self-ignition reaction of sample, allowing its use as sample preparation procedure for further elemental analysis. After optimization, a high sample mass (up to 600 mg of coal and graphite) was efficiently digested using only 4 mol L-1 HNO3 as absorbing solution. Several elements (Ba, Ca, Fe, K, Li, Mg, Na, and Zn) were determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Accuracy was evaluated by using a certified reference material (NIST 1632b). Blanks were negligible, and only a diluted solution was required for analytes absorption preventing residue generation and making the proposed method in agreement with green chemistry recommendations. The feasibility of the proposed method for hard-to-digest materials, the minimization of reagent consumption, and the possibility of multi elemental analysis with lower blanks and better limits of detection can be considered as the main advantages of this method. [ABSTRACT FROM AUTHOR]

Quantitative analysis of the electron accumulation layer formed near nonideal (actual) semiconductor surface causes considerable difficulties. In the present article, for the accumulation layers induced in the subsurface region at the real narrow-gap semiconductor-insulator interface, an effective algorithmic approach providing a simplified self-consistent solution of the Poisson and Schrödinger equations is proposed and discussed. The physical model takes into account the conduction band nonparabolicity, electron gas degeneration, and other dominant features of solids in question; special attention is paid to the existence of semiconductor-dielectric intermediate layer. A novel approximation for the surface electrostatic potential in the form of a modified Кratzer potential is proposed and substantiated. It allows us to obtain the electron wavefunctions and energy spectrum in the analytical form. It is shown that the modified Кratzer potential is a good approximation function applicable at least to subsurface electron accumulation layers induced at the A3B5 narrow-gap semiconductor boundary surface allowing for the existence of a semiconductor-insulator intermediate layer. For the n-InSb nonideal surface, as an example, spatial distribution of electron potential energy, discrete energy spectrum of electrons in the broad range of surface densities (up to 1013 cm-2), and some other physical characteristics are calculated using the proposed algorithm. [ABSTRACT FROM AUTHOR]

Decay and propagation properties of symmetric surface plasmon polariton (SPP) mode based on metal–insulator–metal (MIM) waveguide are investigated numerically. SPP mode is excited through a dipole embedded in Al 2 O 3 layer of Au / Al 2 O 3 / Au structure. We demonstrate that the distance between the dipole and Al 2 O 3 / Au interface is an important tunable parameter to influence the decay properties. The electric/magnetic field intensity horizontal and vertical decay lengths of symmetric SPP mode are 19 nm and 24 nm, respectively. Moreover, the propagation length along Al 2 O 3 / Au interface of symmetric SPP mode depends on Al 2 O 3 layer thickness. The maximal propagation length reaches 0.608 μ m with Al 2 O 3 layer thickness of 100 nm. These values can provide a theoretical reference for designing a high-performance SPP source using Au / Al 2 O 3 / Au structure. [ABSTRACT FROM AUTHOR]

We study the properties of the InSb (001) surface covered with ultrathin KBr films, with a thickness of 1–4 ML. KBr deposition does not strongly perturb the crystallographic structure of the InSb surface and the electronic structure of the substrate also remains unaffected by the overlayer. A simple model of the studied system is proposed, in which a thin KBr layer is treated as a dielectric film, modifying potential barrier for the electrons tunneling to/from the InSb substrate. Apparent step heights on the KBr film, measured using scanning tunneling microscope (STM), agree well with the predictions of the model and the atomically-resolved STM images show the structure of the InSb-KBr interface. Our results demonstrate that STM may be used as a tool for investigations of the semiconductor–insulator interfaces. [ABSTRACT FROM AUTHOR]

The electronic properties of hexagonal boron nitride ( h -BN) are controllable by applying normal pressure. In this work, we perform first-principles density functional calculation to investigate electronic structure of several h -BN bilayers with different stacking patterns under normal pressure. The results suggest that the band gap of h -BN bilayer, surprisingly, undergoes both decreasing and increasing trend with increasing of normal pressure, which is considerably different from monotonously decreasing by applying electric field. Furthermore, it is found that the transformation from a direct- to an indirect-gap can be achieved in the case of stacking pattern II as the pressure above 34.3%. However, the insulator-semiconductor transition can be induced for stacking pattern I and III under similar normal pressure. The studies indicate a unique yet easy pathway to tune the electronic properties of h -BN by normal pressure, which may pave the way for their potential applications as optoelectronic device materials. [ABSTRACT FROM AUTHOR]

We study the problem of glass insulator fault detection from image in this work. It is a challenging task as no reliable electromagnetism cues are available. Since the characteristics of insulator fault are not clear and the positions of the insulator fault are uncertain. Previous efforts have been focusing on insulator classification and the insulator location. Recently, there is mounting evidence that saliency detection are setting new records for various vision applications. On the other hand, considering the particularly structure of insulator, fault detection can be naturally enhanced by morphology problem. Therefore, we in this paper present a saliency and adaptive morphological based insulator fault detection algorithm, aiming to jointly explore the capacity of saliency and morphology. Specifically, we propose an adaptive learning scheme which learns the saliency and morphology in a unified adaptive framework. According to the experiment, we can process most of the circumstances with 92 % accuracy in 0.5 second on average, which suits the Unmanned Aerial Vehicle (UAV) patrol device well. [ABSTRACT FROM AUTHOR]

Applying the bosonization and renormalization group techniques, we study a generalized Hubbard chain incorporating extra off-diagonal hopping processes in the weak regime, and determine rich ground-state phase diagrams. At half filling, in addition to the insulating phases (HI, MI and DI), there exist the superconducting phases (LE and LL). The off-diagonal hopping accounts for the occurrence of insulator-superconductor transition. Away from half filling, the transition from the LL to LE phase takes place, and the insulating phases disappear. The result provides an insignificant insight into unconventional scenarios for Cooper pairing and insulator-superconductor transition. [ABSTRACT FROM AUTHOR]

In this paper the electrical characteristics of metal-insulator-semiconductor (MIS) and metal-insulator-semiconductor-insulator-metal (MISIM) capacitors with (100)-oriented p-type silicon as a substrate under different high- k gate dielectrics (SiO, HfO, LaO and TiO) are investigated in the semi-classical and quantum mechanical models. We review the quantum correction in the inversion layer charge density for p-doped structures. The purpose of this paper is to point out the differences between the semi-classical and quantum mechanical charge descriptions at the insulator-semiconductor interface and the effect of the type of oxide and their position (gate oxide or buried oxide) in our structures. In particular, capacitance-voltage ( C- V), relative position of the sub-band energies and their wavefunctions are studied to examine qualitatively and quantitatively the electron states and charging mechanisms in our devices. We find that parameters such as threshold voltage and device trans-conductance are enormously sensitive to the proper treatment of quantization effects. [ABSTRACT FROM AUTHOR]

We generalize the Stückelberg holographic superconductor model by including dark matter sector in the five-dimensional AdS soliton space-time beyond the probe limit. We study phase transitions with large charge of the scalar field through the condensation of the scalar operator and the holographic topological entanglement entropy of the system. We find that the entanglement entropy is a good probe of the order of phase transitions and second-order critical phase transition points. By investigating the behaviors of the entanglement entropy, we show that the larger coupling parameter makes the first-order phase transition more difficult to happen. In all, we conclude that the entanglement entropy can be used to study the effects of the dark matter sector in this general insulator/superconductor system. [ABSTRACT FROM AUTHOR]

All the iron-based superconductors identified so far share a square lattice composed of Fe atoms as a common feature, despite having different crystal structures. In copper-based materials, the superconducting phase emerges not only in square-lattice structures but also in ladder structures. Yet iron-based superconductors without a square-lattice motif have not been found, despite being actively sought out. Here, we report the discovery of pressure-induced superconductivity in the iron-based spin-ladder material BaFe2S3, a Mott insulator with striped-type magnetic ordering below ∼120 K. On the application of pressure this compound exhibits a metal-insulator transition at about 11 GPa, followed by the appearance of superconductivity below Tc = 14 K, right after the onset of the metallic phase. Our findings indicate that iron-based ladder compounds represent promising material platforms, in particular for studying the fundamentals of iron-based superconductivity. [ABSTRACT FROM AUTHOR]

All the iron-based superconductors identified so far share a square lattice composed of Fe atoms as a common feature, despite having different crystal structures. In copper-based materials, the superconducting phase emerges not only in square-lattice structures but also in ladder structures. Yet iron-based superconductors without a square-lattice motif have not been found, despite being actively sought out. Here, we report the discovery of pressure-induced superconductivity in the iron-based spin-ladder material BaFe2S3, a Mott insulator with striped-type magnetic ordering below ∼120 K. On the application of pressure this compound exhibits a metal-insulator transition at about 11 GPa, followed by the appearance of superconductivity below Tc = 14 K, right after the onset of the metallic phase. Our findings indicate that iron-based ladder compounds represent promising material platforms, in particular for studying the fundamentals of iron-based superconductivity. [ABSTRACT FROM AUTHOR]

In this study, we investigated the effect of yttrium content on the structural properties and sensing characteristics of YbY x O y sensing membranes for electrolyte–insulator–semiconductor (EIS) sensors to detect the rheumatoid factor (RF). The YbY x O y EIS device prepared at the 60 W plasma condition exhibited a higher sensitivity of 65.77 mV/pH, a lower hysteresis voltage of ∼1 mV, and a smaller drift rate of 0.14 mV/h than did those prepared at the other conditions. We attribute this behavior to the optimal yttrium content in the YbY x O y film forming a smooth surface. Furthermore, we used a novel YbTi x O y EIS biosensor to measure the RF antigen in human serum because of its rapid and label-free detection. Two different techniques were used for the immobilization of RF antibody onto the surface of an YbTi x O y EIS sensor. The RF antibody was directly immobilized on the EIS surface modified with 3-aminopropyltriethoxysilane (APTES) followed by glutaraldehyde (GA). In contrast, a mixture of 1-ethyl-3-(3-dimethylamino-propyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) solution was used to functionalize the carboxyl groups at the tail of RF antibodies. RF antibodies functionalized with the active NHS esters were covalently immobilized on the APTES-modified YbTi x O y surface. The immobilized RF antibodies on the EIS that are functionalized with the EDC and NHS exhibit higher (41.11 mV/pC RF ) for detection of serum RF antigen in the range 10 −7 to 10 −3 M, compared to traditional antibody immobilization technique via APTES and GA linkage. The YbTi x O y EIS biosensor is a promising analytical tool for RF antigen monitoring due to its good sensitivity, stability and repeatability. [ABSTRACT FROM AUTHOR]

We investigate theoretically the nonequilibrium transport properties of a topological insulator quantum dot (TIQD) in the Coulomb blockade and Kondo regime. An Anderson impurity model is applied to a TIQD system coupled to two external leads, and we show that the model realizes the spin-orbital Kondo effect at the Dirac point where the edge states are not split by a finite-size effect, leading to an additional SU(4) symmetry because of the presence of strong mixture among four internal degrees of freedom. In a more realistic situation where the degeneracy is lifted due to the finite-size effect, we demonstrate that there is a richer structure in transport measurements. We illustrate a continuous crossover from four (spin and orbital) Coulomb peaks with large interpair spacing and small intrapair spacing to a double-peak structure in the local density of states (LDOS) as increasing the hybridization strength T within the Coulomb blockade regime. When temperature falls below the Kondo temperature TK, four Kondo peaks show up in the nonequilibrium LDOS. Two of them are located at the chemical potential of each lead, and the other two are shifted away from the chemical potential by an amount proportional to the TIQD's bare energy level, leading to a triple-peak structure in the differential conductance when a bias voltage is applied. [ABSTRACT FROM AUTHOR]

We propose a hybrid plasmonic waveguide that incorporates a semiconductor-insulator-metal bow-tie configuration within a low-index gap guarded by semiconductor and metallic nanostructures. Ultratight field confinement (Aeff ~λ2 3100 - λ2/120) in conjunction with reasonable propagation distance (L ~ 56-138 μm) can be achieved simultaneously at a telecommunication wavelength. Compared to a conventional hybrid waveguide, the effective mode area and propagation loss of a typical bow-tie hybrid configuration are reduced by 2-89% and 34-62%, respectively, whereas the figure of merit is enhanced by 53-700%, along with increased power ratio inside the gap region for small gap cases. Studies on fabrication tolerance, waveguide crosstalk, and loss compensation reveal its robust property for practical implementations and remarkable feasibility to realize ultracompact passive and active components. Moreover, we also reveal the broadband feature of the waveguide and show that its concept can be applicable to various other metallic configurations as well, which may open up possibilities for the inventions of numerous high-performance plasmon waveguides and components. [ABSTRACT FROM PUBLISHER]

The quality of the interface between silicon and a dielectric is one of the main influencing parameters for crystalline silicon surface passivation. In this work, this interface is examined by means of capacitance voltage (CV) and nuclear resonance reaction analysis (NRRA) measurements for SiN x :H as well as SiO 2 capped SiN x :H passivated p-type float zone silicon samples. Due to a highly sensitive NRRA measurement setup, very small differences in hydrogen concentration at the interface could be detected for the first time and a significant correlation between hydrogen concentration, interface state trap densities D it and passivation quality is found. The results of this study present easily implementable processes to improve the quality of SiN x :H surface passivation and process stability for solar cell and module production applications. First optimised industrial type Al-BSF p-type cells feature 2 mV and 0.5 mA/cm 2 gains in V oc and j sc , leading to efficiencies of up to 19.1%. [ABSTRACT FROM AUTHOR]

A diamond logic inverter is demonstrated using an enhancement-mode hydrogenated-diamond metal-insulator-semiconductor field effect transistor (MISFET) coupled with a load resistor. The gate insulator has a bilayer structure of a sputtering-deposited LaAlO3 layer and a thin atomiclayer-deposited Al2O3 buffer layer. The source-drain current maximum, extrinsic transconductance, and threshold voltage of the MISFET are measured to be --40.7 mA.mm-1, 13.2 ± 0.1 mS.mm-1, and --3.1 ± 0.1 V, respectively. The logic inverters show distinct inversion (NOT-gate) characteristics for input voltages ranging from 4.0 to --10.0 V. With increasing the load resistance, the gain of the logic inverter increases from 5.6 to as large as 19.4. The pulse response against the high and low input voltages shows the inversion response with the low and high output voltages. [ABSTRACT FROM AUTHOR]

The density of traps at semiconductor-insulator interfaces was successfully estimated using microwave dielectric loss spectroscopy with model thin-film organic field-effect transistors. The non-contact, non-destructive analysis technique is referred to as field-induced time-resolved microwave conductivity (FI-TRMC) at interfaces. Kinetic traces of FI-TRMC transients clearly distinguished the mobile charge carriers at the interfaces from the immobile charges trapped at defects, allowing both the mobility of charge carriers and the number density of trap sites to be determined at the semiconductor-insulator interfaces. The number density of defects at the interface between evaporated pentacene on a poly(methylmethacrylate) insulating layer was determined to be 1012cm-2, and the hole mobility was up to 6.5 cm² V-1 s-1 after filling the defects with trapped carriers. The FI-TRMC at interfaces technique has the potential to provide rapid screening for the assessment of interfacial electronic states in a variety of semiconductor devices. [ABSTRACT FROM AUTHOR]

The effect of thermal annealing and exposure to oxygen plasma on the phase composition, structure, and microprofile of titanium-dioxide films deposited by high-frequency magnetron sputtering on silicon substrates is studied. The influence exerted by processing modes on the capacitance-voltage and conductance-voltage characteristics of Me-TiO-Si-Me structures and on the density of surface states at the semiconductor-insulator interface is examined. It is shown that TiO films are amorphous upon their fabrication. Upon the annealing of films at 500°C in an argon atmosphere, crystallites of anatase and rutile appear in the amorphous matrix. The treatment of a titanium-dioxide film in oxygen plasma gives rise to rutile crystallites with new crystallographic planes. As a result of annealing at 750°C, the anatase phase disappears and the film becomes polycrystalline, containing only rutile crystallites. The capacitance of Me-TiO-Si-Me structures in the accumulation mode reaches the maximum value upon annealing at 750°C, which is due to the transformation of titanium dioxide to the rutile phase. The specific capacitance is 5.9 × 10 F/cm. The decrease in the capacitance of the structures and in the amount of fixed charge in the insulator upon exposure to oxygen plasma is due to the diffusion of oxygen atoms across the titanium-dioxide layer to give a SiO film at the TiO-Si interface. As a result of the annealing and treatment of a titanium-dioxide film in oxygen plasma, the energy density of surface states decreases by more than an order of magnitude as compared with the unannealed samples. [ABSTRACT FROM AUTHOR]

The quasiparticle bands of diamond, a prototype covalent insulator, are herein studied by means of a wave-function electronic-structure theory, with emphasis on the nature of the correlation hole around a bare particle. Short-range correlations are in such a system conveniently described by using a real-space representation and many-body techniques from ab initio quantum chemistry. To account for long-range polarization effects, on the other hand, we adopt the approximation of a dielectric continuum. Having as "uncorrelated" reference the Hartree-Fock band structure, the post-Hartree-Fock treatment is carried out in terms of localized Wannier functions derived from the Hartree-Fock solution. The computed correlation-induced corrections to the relevant real-space matrix elements are important and give rise to a strong reduction, in the range of 50%, of the initial Hartree-Fock gap. While our final results for the indirect and direct gaps, 5.4 and 6.9 eV, respectively, compare very well with the experimental data, the width of the valence band comes out by 10% to 15% too large as compared to experiment. This overestimation of the valence-band width appears to be related to size-consistency effects in the configuration-interaction correlation treatment. [ABSTRACT FROM AUTHOR]

Abstract: A CeO2-based multi-analyte electrolyte–insulator–semiconductor (EIS) biosensor has been fabricated on silicon substrate. To enhance the material quality and sensing performance, annealing treatment in N2 and O2 ambient has been incorporated. To examine the annealing effects, material analyses were conducted using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) to identify optimal treatment conditions. Furthermore, sensing performance for various ions of Na+, K+, urea, and glucose has also been tested. Results indicate that the membrane annealed at 800°C in O2 ambience exhibited a better performance with higher multianalyte sensitivity and a lower drift rate compared with the membrane annealed in N2 ambience. Oxygen in O2 ambience may cause stronger reflow and fill in the oxygen vacancy so that the material properties and sensing capability can be improved in O2 annealing ambience. [Copyright &y& Elsevier]

A combination of deep level optical spectroscopy and lighted capacitance voltage profiling has been used to analyze the effect of N into the energy levels close to the valence band of Zn0.9Mg0.1O. Three energy levels at EV+0.47 eV, EV +0.35 eV, and EV+ 0.6 eV are observed in all films with concentrations in the range of 1015-1018 cm-3. The two shallowest traps at EV+0.35 eV and EV+0.16 eV have very large concentrations that scale with the N exposure and are thus potential acceptor levels. In order to correctly quantify the deep level concentrations, a metal-insulator-semiconductor model has been invoked, explaining well the resulting capacitance-voltage curves. [ABSTRACT FROM AUTHOR]

We have produced stable organic field-effect transistors (OFETs) with an ultra-thin HfO2 gate insulator deposited directly on top of rubrene single crystals by atomic layer deposition (ALD). We find that ALD is a gentle deposition process to grow thin films without damaging rubrene single crystals, as results these devices have a negligibly small threshold voltage and are very stable against gate-bias-stress, and the mobility exceeds 1 cm²/V s. Moreover, the devices show very little degradation even when kept in air for more than 2 months. These results demonstrate thin HfO2 layers deposited by ALD to be well suited as high capacitance gate dielectrics in OFETs operating at small gate voltage. In addition, the dielectric layer acts as an effective passivation layer to protect the organic semiconductor. [ABSTRACT FROM AUTHOR]

One of the most intensely studied scenarios of high-temperature superconductivity (HTS) postulates pairing by exchange of magnetic excitations. Indeed, such excitations have been observed up to optimal doping in the cuprates. In the heavily overdoped regime, neutron scattering measurements indicate that magnetic excitations have effectively disappeared, and this has been argued to cause the demise of HTS with overdoping. Here we use resonant inelastic X-ray scattering, which is sensitive to complementary parts of reciprocal space, to measure the evolution of the magnetic excitations in La2−xSrxCuO4 across the entire phase diagram, from a strongly correlated insulator (x = 0) to a non-superconducting metal (x = 0.40). For x = 0, well-defined magnon excitations are observed. These magnons broaden with doping, but they persist with a similar dispersion and comparable intensity all the way to the non-superconducting, heavily overdoped metallic phase. The destruction of HTS with overdoping is therefore caused neither by the general disappearance nor by the overall softening of magnetic excitations. Other factors, such as the redistribution of spectral weight, must be considered. [ABSTRACT FROM AUTHOR]

Highlights: [•] Cell growth and metabolism were continuously and synchronously monitored by cellular impedance sensing and LAPS based on the same sensor structure. [•] Electrolyte-insulator-semiconductor (EIS) structure was used as the sensor structure. [•] Equivalent circuit model for cellular impedance sensing was build. [•] Cytotoxicity of heavy metal Cadmium (Cd) was evaluated. [Copyright &y& Elsevier]

The principle of quasi-equilibrium in the study of the structures that contain semiconductors and insulators, in particular, dielectric films in the metal-insulator-semiconductor (MIS) structures is discussed. A possibility of the simultaneous measurements of the averaged convection currents in an insulator and the current flows through the semiconductor-insulator interface in the MIS structures is considered. The methods for the measurement of the concentration of mobile ions in a dielectric film are analyzed. [ABSTRACT FROM AUTHOR]

We describe in detail the principles of designing a tunable mixer with suppression of the mirror channel for the frequency band 86-115 GHz and a mixer for the band 787-950 GHz with twochannel reception and absence of the mechanical-tuning components. The mixers are based on superconductor-insulator-superconductor tunnel superconducting junctions with normal metal (aluminum) in the tuning circuit. The two developed mixers are optimized for the one-side chip connection to the full-height rectangular waveguide, which is required for creating a submillimeterwave single-chamber balanced waveguide mixer with a wide intermediate frequency bandwidth. The input-signal reflection coefficient is below −15 dB and the loss of the signal transmission to the mixer is below 3 dB in the frequency band 787-950 GHz. [ABSTRACT FROM AUTHOR]

Abstract: This work presents a novel insight to the aspects of silicon surface passivation and the influence of thin intermediate layers generated by chemically grown silicon oxides. Strong light induced effects on passivation properties are investigated. After exposure to light (0.25 suns) for about 60 s, samples based on a PECVD layer system consisting of SiNx and SiO2 deposited on crystalline silicon with native silicon oxides show an improvement of more than 100% in minority carrier lifetime. These improvements are stable over months and lead to effective surface recombination velocities as low as 10cm/s on chemically polished p-type FZ wafers. With the use of different light sources, corona charging and annealing experiments the effect is investigated in detail. Finally, the effect is proposed to be a photo induced curing process of defects in the Si/SiO2 interface with the incorporation of hydrogen. [Copyright &y& Elsevier]

Metal-induced crystallization has allowed for high-quality Si and Ge thin films on insulators at low temperatures; however, there has been difficulty for SiGe alloys of intermediate compositions. Here we demonstrate a large-grained (> 100 μm), 99% (111)-oriented Si 0.4 Ge 0.6 layer on a glass substrate through layer exchange between Al and amorphous Si 0.4 Ge 0.6 layers. Slow annealing below 350 °C is a key to suppressing nucleation and facilitating lateral growth. The use of the (111)-oriented SiGe layers as epitaxial templates will pave the way for integrating various materials monolithically on three-dimensional Si large-scale integrated circuits and on multi-functional displays. [ABSTRACT FROM AUTHOR]

The optical properties of a SiOx film rapid-thermal-annealed (RTA) by CO2 laser are primarily investigated. The microphotoluminescence (mu-PL) and high-resolution transmission electron microscopy (HRTEM) analyses indicate that the precipitation of random-oriented Si nanocrystals can be initiated when laser intensity (Plaser) is larger than 4.5 kW/cm2. At Plaser of 6kW/cm2, the Si nanocrystal exhibits a largest diameter of 8 nm and a highest density of 4.5times1016 cm-3, which emits strong PL at 790-825 nm. The microphotoreflectance of the CO2 laser RTA SiOx film reveals a volume density product dependent refractive index increasing from 1.57 to 1.87 as Plaser increases from 1.5 to 7.5 kW/cm2. Nonetheless, the laser ablation of the SiOx film occurs with a linear ablation slope of 35 nm/kW/cm2 at beyond 7.5 kW/cm2, which terminates the enlargement of Si nanocrystals, degrades the near-infrared PL, and slightly reduces the refractive index of the CO 2 laser RTA SiOx film [ABSTRACT FROM PUBLISHER]

We report the experimental results of Fe and Fe3O4 nanostructures on GaAs(100) surfaces and hybrid Ferromagnetic/Semiconductor/Ferromagnetic (FM/SC/FM) spintronic devices. Element specific x-ray magnetic circular dichroism (XMCD) measurements have shown directly that Fe atoms on the GaAs(100)-4times6 surface are ferromagnetic. Within coverages of 2.5 to 4.8 ML superparamagnetic nanoclusters are formed and exhibiting strong uniaxial anisotropy, of the order of 6.0times105 erg/cm3. The coercivities of epitaxial Fe dot arrays films grown on GaAs(100) were observed to be dependent on the separation and size of the dots indicating that interdot dipolar coupling affects the magnetization processes in these dots. In addition Fe3O4 films grown on deformed GaAs(100) substrates have been observed to form nanostripes following the topography of the substrate and magneto-optical Kerr effect (MOKE) measurements showed that these nanostripes have uniaxial magnetic anisotropy with easy axis perpendicular to the length of the nanostripes. Meanwhile the FM/SC/FM vertical device has exhibited a biasing current dependent on MR characteristics, with a maximum change of 12% in the MR observed, indicating for the first time a large room temperature spin injection and detection [ABSTRACT FROM PUBLISHER]

We explore the breakdown of universal mobility behavior in sub-100-nm Si MOSFETs, using a novel three-dimensional (3-D) statistical simulation approach. In this approach, carrier trajectories in the bulk are treated via 3-D Brownian dynamics, while the carrier-interface roughness scattering is treated using a novel empirical model. Owing to the high efficiency of the transport kernel, effective mobility in 3-D MOSFETs with realistic Si-SiO2 interfaces reconstructed from a Gaussian or exponential correlation function can be simulated in a statistical manner. We first demonstrate a practical calibration procedure for the interface mobility and affirm the universal behavior in the long channel limit. Next, effective mobility in ensembles of MOSFETs with a gate length down to 10 nm is investigated. It is found that the random-discrete nature of the Si-SiO2 interface leads to a distribution of carrier mobility below the interface, which can deviate considerably from universal mobility curves when Lgate<6Λ, where Λ is the correlation length for the SiO2 interface. [ABSTRACT FROM PUBLISHER]

In this paper we present an overview of nanocrystal memories - a nascent nonvolatile memory technology that promises to extend the scaling of more conventional charge storage devices to nanometer-scale dimensions [ABSTRACT FROM PUBLISHER]

Many research groups have used stress-induced leakage current SILC as a mean to measure the oxide traps (defects) buildup in the oxide film during electrical stress. It is commonly believed that these very same traps will lead to oxide breakdown when their density reaches a critical value. We studied the annealing kinetic of SILC as well as, the oxide breakdown distribution and found that they are quite different. Our result casts serious doubt on the validity of the popular assumption [ABSTRACT FROM PUBLISHER]

In this letter, we study the electronic properties of InGaAs and Si trigates using the nonparabolic effective mass approximation and up-to-date mobility models. Our comprehensive simulations estimate a strong reduction of the InGaAs electron mobility to values even lower than those achieved with Si. Considering the reduction of the gate capacitance due to the low density-of-states of the III-V alloy, no apparent benefit would be obtained from using InGaAs trigates instead of Si ones unless high quality interfaces can be achieved. We conclude that the potential application of InGaAs trigates as a reference device for future technological nodes is seriously jeopardized by the quality of the semiconductor-insulator interface. [ABSTRACT FROM PUBLISHER]

Photonic bandgap (PBG) waveguide microcavities with tightly confined resonant optical modes have been designed, fabricated using high-dielectric-contrast GaAs/AlxOy III-V compound semiconductor structures, and characterized optically. The photonic crystal lattices are defined by one-dimensional (1-D) arrays of holes in waveguides, and a controlled defect in the spacing between two holes of an array defines a microcavity. Waveguide microcavity resonances have been studied in both monorail and suspended air-bridge geometries. Resonance states with cavity Q's as high as 360 were measured at wavelengths near 1.55 μm, with modal volumes as small as 0.026 μm, which corresponds to only two times (λ/2n)3 [ABSTRACT FROM PUBLISHER]

An electric-field induced technique has been successfully utilized to control the phase separation and the interfaces of semiconductorinsulator composite film, which provided a new research approach for scientists working in related fields. [ABSTRACT FROM AUTHOR]

Trenches are fundamental structures used to build advanced optical planar waveguide components. In this letter, the fabrication of trenches across silica-on-silicon waveguides using inductively coupled plasma etching is presented. These trenches were etched deep into the silicon substrate and their widths were varied between 24 and 100 μm. The insertion loss for waveguides with 24- and 28-μm-wide trenches etched across them were measured for trenches filled with air and oil. The measured results followed those expected from simulations. [ABSTRACT FROM PUBLISHER]