Interface scattering dominated carrier transport in hysteresis-free amorphous InGaZnO thin film transistors with high-k HfAlO gate dielectrics by atom layer deposition

In this work, we systematically investigated the carrier transport of hysteresis-free amorphous InGaZnO (a-IGZO) thin film transistors (TFTs) incorporating high-k (HfO2)x(Al2O3)y gate dielectrics with different composition and permittivity by atomic layer deposition (ALD). A dielectric surface morphology dominated interface scattering carrier transport mechanism is demonstrated, and the effect of the dielectric polarization and the interface states on the carrier mobility is discovered in TFT devices gated by high quality dielectrics with negligible charge trap effect. Accordingly, an a-IGZO TFT gated by (HfO2)0.5(Al2O3)0.5 dielectric with the smoothest surface exhibits the best performance in terms of a preferable field-effect mobility of 18.35 cm2 V-1 s-1, a small subthreshold swing of 0.105 V decade-1, a high on/off current ratio of 4.6× 106, and excellent stability under positive bias stress.

Sign reversal of anomalous Hall effect derived from the transformation of scattering effect in cluster-assembled Ni0.8Fe0.2 nanostructural films

Both surface and interface scattering induced a sign reversal of anomalous Hall effects (AHE) in a few heterostructures. The sign reversal exiting in a single-substance can clarify the role of...

Design and Preparation of a 6-Channel Fan-Shaped Integrated Narrow-Band Filter in the Mid-Infrared Band

A six-channel fan-shaped integrated narrow-band filter on a silicon substrate was designed on the basis of the Fabray–Perot (FP) theory and was fabricated using e-beam thermal evaporation. The central wavelength was modulated by modifying the FP cavity thickness using the combination mask method. Germanium and zinc sulfide were selected as the high and low refractive index film materials, respectively. Its average peak transmission reached 83.3%, the cut-off transmittance was less than 1%, and the full width at half maximum (FWHM) changed from 55 and 94 nm, and the central wavelength positioning accuracy error was less than 0.35%. Furthermore, transmittance was also calculated inversely, using the thickness of each layer of films, in order to deduce the reason of the decrease in peak transmittance. Thickness deviation of each layer and interface scattering contributed to the decrease of peak transmittance. Compared with the same type of products in the market, our filter showed better properties than that of some published and commercial filter.

Strong interface scattering induced low thermal conductivity in Bi-based GeTe/Bi2Te3 superlattice-like materials

Strong interface scattering caused by Bi atoms in Bi-based GeTe/Bi2Te3 superlattice-like materials leads to the decrease of thermal conductivity.

Anisotropic Thermal Conduction in Transition Metal Dichalcogenide Nanocomposites with Rough Interfaces

We present a theory of thermal conduction in a transition metal dichalcogenide nanocomposite structure with rough interfaces that accounts for the anisotropic conductivities of the host, the insert and the interface regions. The host and insert conductivities are calculated using a semi ab-initio method. The effects of specularity in phonon interface scattering and the thermal boundary resistance is incorporated through linking a phonon wavevector dependent specular scattering parameter to the average height of surface inhomogeneities, and the conductivity of the composite is calculated by employing an extension of a modified effective medium approach. Our work for spherical inserts of WS 2 in MoS 2 predicts that the effects of specular scattering due to surface roughness is more pronounced for inserts smaller than 100 nm, even at volume fractions of the order of 0.05.

A three-dimensional bistatic reverberation model of underwater explosion by interface scattering at variable sound speeds

Underwater reverberation is a main limitation of the sonar performance and thereby the reverberation level estimation becomes crucial. In this study, based on the Lambert law and ray theory, a model for predicting 3D bistatic reverberation performance by interface scattering at linear sound speed profile is established and then verified through the underwater explosion experiments. The Influences of source and receiver positions, and relative sound speed gradient on reverberation performance are further investigated. The results indicate that: (1) the proposed model can predict the short-range mean reverberation level effectively, with the deviation 2–4 dB and describe the whole reverberation level distribution in some details; (2) at the early reverberation phase, the interference effects between the interface scattering sounds are considerable and a dominating interface exists; the counterbalance between the losses by scattering, spreading and medium absorption results in the local high-intensity zones close to corresponding interfaces, respectively; (3) as the sound source moves towards some interface, associated local high-intensity zone gradually expands, while the other one shrinks; if the sound speed approaches are constant, an extra local high-intensity zone will appear between the previous two but with a lower magnitude.

Experimental Study of (Water–Oil) Flow Patterns and Pressure Drop in Vertical and Horizontal Pipes

This paper provides the results of experimental stream flow patterns (water–oil) investigated in vertical and horizontal pipes with an elbow. The pipes are made from Perspex; the inner diameter is 0.024[Formula: see text]m, and the lengths of the vertical and horizontal pipes are 6 and 3[Formula: see text]m, respectively. The values of pressure at the four locations where [Formula: see text], 138, 248, and 304 are measured in various cases. The superficial velocities of the water range from 0.1 to 0.4[Formula: see text]m/s and of the oil from 0.1 to 0.9[Formula: see text]m/s. The pressure decreases with an increase in the height and the speed. Droplet/elongated/churn and annular streams are observed in a vertical pipe. The flow patterns are the stratified wavy stream with droplets at the interface, scattering (dispersion) of oil in water with a water layer, and annular flow in the horizontal pipe. These results of flow patterns are determined by a digital camera.