Erratum: Temperature dependence of 1∕f noise mechanisms in silicon nanowire biochemical field effect transistors [Appl. Phys. Lett. 97, 243501 (2010)

[This corrects the article on p. 243501 in vol. 97, PMID: 21221250.][This corrects the article on p. 243501 in vol. 97, PMID: 21221250.].     

Temperature dependence of In1−xGaxSb reflectivity in the far infrared

Far infrared reflectivity spectra of polycrystalline In_1?xGa_xSb were measured and numerically analyzed using the classical dispersion formula and also a fitting procedure based on the modified plasmon-phonon interaction model in the temperature range from 10 K to 300 K. Optical parameters were calculated and discussed. A local mode belonging to the GaSb rich end and two-mode behavior were observed at low temperatures.     

Temperature dependence of the pseudogap in Y1−zPrzBa2Cu3O7−δ single crystals

We investigate the conductivity in the basis plane of Y_1?zPr_zBa₂Cu₃O_7?δ and YBa₂Cu₃O_7?δ single crystals. The excess conductivity, Δσ, is described by Δσ ~ (1 ? T/T*)exp(Δ_ab*/T) in a wide temperature range T_f < T < T*, where T* is the mean field temperature of the superconducting transition. We determine that the temperature dependence of the pseudogap (PG) is described in terms of the BCS-BEC crossover theoretical model. It is observed that a reduction in the praseodymium content results to the widening of the temperature interval that the PG region is realized and a narrowing of the area of existence of the linear dependence of the resistivity, ρ(T), in the ab plane.     

Temperature dependence of F → X reaction based holographic recording in electrolytically coloured KBr crystals

Abstract

The temperature dependence of the F → X reaction based holographic recording of the electrolytically coloured KBr crystals is studied. It was observed that the maximum diffraction efficiency of the volume gratings varied with the recording temperature in the range 160–220°C. The optimal temperature was found to depend on the initial optical density of the F-centres. It decreased with increasing optical density.     

Temperature dependence of impact toughness in Al–Li–Cu–Mg–Zr alloys

Abstract

The dependence on temperature of the impact toughness in Al–Li–Cu–Mg–Zr alloys was investigated focusing on the low temperature impact toughness. The impact toughness of Al–Li–Cu–Mg–Zr alloys in the low temperature region (≤ 423 K) increased with decreasing temperature. Laminated cracks, the number of which increased with the increase in impact toughness in the low temperature region, were observed and it was suggested that the appearance of these cracks resulted in part of the increase of the impact toughness of this alloy. The spectra of potassium and sodium were detected from the fracture surface of a specimen tested at room temperature. This indicates that a low melting point metal phase seems to affect the impact toughness near room temperature, i.e. this phase seems to produce the liquid metal embrittlement locally at the grain boundary.

MST/787     

Temperature dependence of the luminescence intensity in optical fibers of oxyfluoride glass with CdS and CdS x Se1 − x quantum dots

The temperature dependences of the integral luminescence intensity in optical fibers of oxyfluoride glass with CdS and CdS _x Se_{1 ? x} quantum dots have been studied in a temperature range of 25–250°C. It is established that heating in this range leads to luminescence quenching in accordance with a nearly linear law. This effect can be used for the creation of fiber-optic temperature sensors.     

Andreev reflection on the Ag−BaPb1−x Bi x O3 microconstriction: Temperature and magnetic field dependence

The point-contact spectroscopy has been performed on the normal metal-superconductor microconstriction Ag?BaPb_1?xBi_xO₃. The conductance curves of our junctions reveal almost ideal Andreev reflection behavior described by theBlonder-Tinkham-Klapwijk theory, with the in-gap conductance twice higher than the conductance at higher voltages. We studied the effect of the temperature and magnetic field on the Andreev reflection. The temperature dependence of the energy gap (determined from the BTK theory) follows the BCS prediction. The value of the reduced gap yields a weak coupling strength in BaPb_1?xBi_xO₃. ¿From magnetic measurements up to 10 Tesla the temperature dependence of the upper critical field H_c2 has been determined and found to follow the Werthamer-Helfand-Hohenberg prediction.     

Annealing effect on the structural,electrical and 1/f noise properties of Mn–Co–Ni–O thin films

Thin films of Mn_1.4Co_1.0Ni_0.6O₄ (MCN) spinel oxide are grown by radio frequency (RF) magnetron sputtering method on amorphous Al₂O₃ substrate. We investigate the annealing effect on the micro structural and electrical properties of RF sputtered MCN films. It is found that the crystallinity of MCN film is improved with increasing annealing time at 750 °C, and the annealed films present excellent cubic spinel (220) preferred orientation in X-ray diffraction patterns. Comparing to as-sputtered thin film, the annealed films show a decrease of 60 to 70 % in resistivity at 300 K. The annealed samples with post annealing time longer than 18 min acquire a negative temperature coefficient of resistance of about ?3.73 %K^?1 and resistivity of about 210–220 Ω cm at 300 K. 1/f noise of MCN films are also studied and the Hooge’s parameters (γ/n) are calculated. After annealing for 18 to 90 min, the γ/n values of the films are on the order of 10^?21 cm³, which ranks about two orders lower than that of amorphous silicon.     

The effect of residual stresses in the ZnO buffer layer on the density of a ZnO nanowire array

Density control is a valuable concern in the research of ZnO nanowire arrays. In this study, unannealed and annealed ZnO thin films were used as substrates to fabricate ZnO nanowire arrays. In the unannealed thin film, an inhomogeneous distribution of the nanowire array was found: the density of nanowires decreases with the increase of distance to the edge. In the annealed thin film, the density of nanowire array becomes larger and more homogeneous. Moreover, nanowires are found in high density along microcracks. It is proposed that the residual stresses in the thin film and the density of the nanowire array are in inverse proportion, leading to the results mentioned above. The relationship between residual stresses and the density of nanowires will have potential applications in modifying the density of ZnO nanowire arrays.     

The effect of beta radiation on Si-I → Si-II phase transformations in silicon under an indenter

The phase transition from a diamond-like crystalline lattice of the Si-I phase to the β-tin type structure of the Si-II phase has been studied by measuring electric resistance under an indenter incorporated into a narrow (d ≈ 2 μm) crevice between metal contacts. It was established that the relative volume fraction of the metalized Si-II phase formed during indentation decreases under the action of a low dose (fluence F = 3.24 × 10¹⁰ cm^?2) of low-intensity (I = 1.8 × 10⁵ cm^?2 s^?1) beta radiation.     

Effects of a high-gradient magnetic field on the migratory behavior of primary crystal silicon in hypereutectic Al–Si alloy

Abstract

The migration of primary Si grains during the solidification of Al–18 wt%Si alloy under a high-gradient magnetic field has been investigated experimentally. It was found that under a gradient magnetic field, the primary Si grains migrated toward one end of the specimen, forming a Si-rich layer, and the thickness of the Si-rich layer increased with increasing magnetic flux density. No movement of Si grains was apparent under a magnetic field below 2.3 T. For magnetic fields above 6.6 T, however, the thickness of the Si-rich layer was almost constant. It was shown that the static field also played a role in impeding the movement of the grains. The primary Si grains were refined in the Si layer, even though the primary silicon grains were very dense. The effect of the magnetic flux density on the migratory behavior is discussed.     

Magnetic field dependence of zero-sound attenuation close to the pair-breaking edge in3He-B due toJ=1−,J z =±1 collective modes

Our previous theory yielded for the Zeeman splitting of the imaginaryJ=1 collective mode in³He-B the result =2+0.25J _z ( is the effective Larmor frequency). In this paper we take into account the downward shift of the pair-breaking edge from 2 to 2₂– (₂ and ₁ are the longitudinal and transverse gap parameters). This leads to a complex Landé factor: the frequencies of theJ _z =±1 components become =2+0.39J _z , and the linewidths of these resonances become finite: =0.18. The coupling amplitudes of theJ _z =±1 components to density are found to be proportional to gap distortion, (₁–₂/(/)². Our results for the ultrasonic attenuation due to theJ _z =±1,J=1 modes are capable of explaining the field dependence of the attenuation close to the pair-breaking edge as observed by Dobbs, Saunders, et al. The observed peak is caused by theJ _z =–1 component: its height increases due to gap distortion as the field is increased, and the peak shifts downward in temperature and its width increases with the field due to the complex Landé factor. TheJ _z =+1 component gives rise to a corresponding dip relative to the continuum attenuation.     

Formation of silicon hollow spheres via electromagnetic levitation method under static magnetic field in hydrogen–argon mixed gas

A formation mechanism of a silicon hollow sphere via electromagnetic levitation method under high static magnetic field in hydrogen atmosphere is discussed in this paper. Since the convection in the levitated silicon melt which is caused by the electromagnetic field is restrained by a high static magnetic field, it is possible to examine a solidification of silicon from an equilibrium silicon melt with hydrogen except an effect of convection. The solidified silicon sphere has an extrusion which is formed during the solidification due to reduced stress in the melt. When a nucleation of pore occurs before the formation of the extrusion, a silicon hollow sphere is formed. Since the chance to form the nucleation of pore increases with increasing hydrogen concentration in the melt, a silicon hollow sphere is formed when the solidification is performed in higher hydrogen partial pressure. In the present case, a silicon hollow sphere is formed by the solidification in 50%H₂–50%Ar atmosphere. However, non-porous silicon spheres are formed by the solidification in 25%H₂–75%Ar or 100%Ar atmosphere.     

Quasi-two-dimensional β-Ga2O3 field effect transistors with large drain current density and low contact resistance via controlled formation of interfacial oxygen vacancies

Nano Research - Quasi-two-dimensional (2D) β-Ga2O3 is a rediscovered metal-oxide semiconductor with an ultra-wide bandgap of 4.6–4.9 eV. It has been reported to be a promising material...     

Temperature dependence of the dielectric properties of mesoporous silica films prepared by a sol–gel route in the presence of polyether modified polydimethylsiloxane

Mesoporous silica films were prepared from tetraethylorthosilicate by an acid-catalyzed sol–gel process in the presence of side-chain polyether modified polydimethylsiloxane. The samples were characterized using Fourier transform infrared spectroscopy, differential thermal analysis and thermogravimetric analysis, field emission scanning electron microscopy, and atomic force microscopy. Furthermore, the dielectric properties of the silica films annealed at different temperatures were investigated at frequencies ranging from 1 to 200 kHz. In addition, the temperature dependence of the dielectric properties of as-prepared porous silica films is discussed in detail.     

Temperature dependence of elastic and dielectric properties of (Bi2O3)1 − x(CuO)x oxide glasses

Oxide glasses with the general formula (Bi₂O₃)_{1 - x}(CuO)_x have been prepared by quick quenching technique. Their longitudinal and shear elastic moduli have been determined by measuring the corresponding ultrasonic wave velocities between 300 and 470 K, which are well below the glass transition temperature of this system. Temperature variation of ultrasonic velocity and attenuation exhibit anomalies around 435 K in glasses with x 0.3. A nonlinear behaviour is also reflected in the CuO concentration dependent dielectric constant curve around x = 0.3. These anomalies are interpreted in terms of a structural softening (or transformation) taking place in samples having CuO concentration above the critical value. The high dielectric constant of these glasses show very little increase with increase of temperature. Anomalies are also found in the temperature dependence of dielectric constant around 435 K. This behaviour is again considered to be associated with the softening of the glass network.     

Use of high-purity AlxGa1−x as layers in epitaxial structures for high-power microwave field-effect transistors

The fabrication of high-purity layers of Al_xGa_1−x As solid solutions in the range 0⩽x⩽0.38 by molecular beam epitaxy is reported. The low-temperature photoluminescence spectra of these layers reveal predominantly the free exciton recombination line (X). The narrow width of the X line, the high intensity ratio of this line to that of the band-acceptor transition line, and the linear dependence of the X line intensity on the excitation power density in the range between 1×10⁻⁴ and 100V·cm⁻² indicate a low concentration of background impurities in these layers. Using this material in pseudomorphic AlGaAs/InGaAs/GaAs heterostructures for high-power microwave transistors produced devices with a specific saturated output power of 0.9 W/mm at 18 GHz. Pis’ma Zh. Tekh. Fiz. 25, 8–15 (August 12, 1999)     

Structural and Mössbauer effect investigations of amorphous FeCuNbSiB alloys nanocrystallized (VITROPERM) in magnetic field

Melt-spun amorphous ribbons of nominal composition Fe73Cu1Nb3Si16B7, annealed at 560-580 degrees C for 1 hour in a magnetic field (H) applied along the width in the ribbon plane, develop uniaxial magnetic anisotropy with easy axis along H and exhibit several novel attributes. The samples labelled as S20 and S150 are nanocomposites consisting of ferromagnetic nanocrystalline grains (volume fraction approximately equal to 84% and 81%) of mean size d = 13(2) nm embedded in a ferromagnetic amorphous matrix and possess a magnetic permeability as large as 20,000 and 150,000, respectively. While nearly 55% of the nanocrystalline grains have a cubic DO3 Fe3Si-like structure with actual Si concentration of about 22 at.%, the remaining 45% nanocrystalline grains have tetragonal Fe3B and hexagonal Fe2Si structure. Since the crystalline volume fraction of Fe3B and Fe2Si nanocrystals is more in the sample S20, this sample exhibits stronger local magnetic anisotropy and hence lower permeability.