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In this letter, we develop the theory of Hall effect driven by non-collinear magnetic textures (topological Hall effect—THE) in diluted magnetic semiconductors (DMSs). We show that a carrier spin-orbit interaction induces a chiral magnetic ordering inside a bound magnetic polaron (BMP). The inner structure of non-collinear BMP is controlled by the type of spin-orbit coupling, allowing us to create skyrmion- (Rashba) or antiskyrmion-like (Dresselhaus) configurations. The asymmetric scattering of itinerant carriers on polarons leads to the Hall response which exists in weak external magnetic fields and at low temperatures. We point out that DMS-based systems allow one to investigate experimentally the dependence of THE both on a carrier spin polarization and on a non-collinear magnetic texture shape. [ABSTRACT FROM AUTHOR]

We investigate temperature-dependent spectral linewidths of Bloch oscillations in biased semiconductor superlattices experimentally and theoretically. The spectral linewidth in a GaAs-based superlattice determined by terahertz emission spectroscopy becomes larger gradually as temperature increases from 80 to 320 K. This behavior can be quantitatively reproduced by a microscopic theory of the spectral linewidth that has been extended to treat the phonon scattering and interface roughness scattering of electrons on a Wannier-Stark ladder. A detailed comparison between the terahertz measurements and theoretical simulations reveals that the LO phonon absorption process governs the increase in the spectral linewidth with increasing temperature. [ABSTRACT FROM AUTHOR]

The inability to scale supply voltage and hence reduce power consumption remains a serious challenge in modern nanotransistors. This arises primarily because the Sub-threshold Swing (SS) of the thermionic MOSFET, a measure of its switching efficiency, is restricted by the Boltzmann limit (kBT/q=60 mV/dec at 300 K). Tunneling FETs, the most promising candidates to circumvent this limit, employ band-to-band tunneling, yielding very low OFF currents and steep SS but at the expense of severely degraded ON currents. In a completely different approach, by introducing concurrent tuning of thermionic and tunneling components through metal/semiconductor Schottky junctions, we achieve an amalgamation of steep SS and high ON currents in the same device. We demonstrate sub-thermionic transport sustained up to 4 decades with SSmin~8.3 mV/dec and SSavg~37.5(25) mV/dec for 4(3) dec in few layer MoS2 dual gated FETs (planar and CMOS compatible) using tunnel injected Schottky contacts for a highly scaled drain voltage of 10 mV, the lowest for any sub-thermionic devices. Furthermore, the same devices can be tuned to operate in the thermionic regime with a field effect mobility of ~84.3 cm2 V-1 s-1. A detailed mechanism involving the independent control of the Schottky barrier height and width through efficient device architecture and material processing elucidates the functioning of these devices. The Gate Tunable Thermionic Tunnel FET can function at a supply voltage of as low as 0.5 V, reducing power consumption dramatically. [ABSTRACT FROM AUTHOR]

Using molecular dynamics simulations, we investigate the thermal conductivity and local heat flux distribution of Bi2Te3 nanowires. It is found that at room temperature, the converged lengthindependent thermal conductivity of Bi2Te3 nanowires is only 0.89 W/m K, which is about 2-fold lower than their bulk counterpart. Interestingly, the local heat flux density along the quintet boundary layer is only about 18% of that along the central layers due to different phonon edge scattering intensities. Our work demonstrates that topological insulator nanostructures are promising candidates for the development of high-performance thermoelectric devices for applications in nanoscale energy generation and temperature management. [ABSTRACT FROM AUTHOR]

We study the extent of ballistic and diffusive thermal transport and the range of application of the Casimir and Fourier theories in semiconductor materials by using a theoretical model based on the Boltzmann transport equation. We show that combined effects of length scale, temperature, and boundary roughness are responsible for thermal transport transitions in silicon nanowires and thin films. We also introduce a more accurate principle for ballistic transport that considers the balance between internal and surface scattering. Phonon quantum confinement effects as well as the conditions for phonon wave interference in nanoscale heat transport are discussed. [ABSTRACT FROM AUTHOR]

We theoretically investigate the use of energetically sharp resonances of core-shell nanoparticles embedded in semiconductors to selectively scatter carriers and thereby enhance the thermoelectric power factor and figure of merit. Appropriate selection of materials for the core-shell band structure can lead to the formation of quasi-bound states inside the nanoparticles, which strongly scatter carriers near these energy levels, making sharp features in the energy-dependent electron relaxation time. We find that the power factor of PbTe at 80 K is enhanced by more than 80% when core-shell nanoparticles of 3 nm core diameter and 1.5 nm shell width are introduced with density 1 × 1018 cm-3. [ABSTRACT FROM AUTHOR]

Here, we report a simple, alternative route towards high-mobility structures of the small-molecular semiconductor 5,11-bis(triethyl silylethynyl) anthradithiophene that requires one single processing step without the need for any post-deposition processing. The method relies on careful control of the casting temperature of the semiconductor and allows rapid production of transistors with uniform and reproducible device performance over large areas. [ABSTRACT FROM AUTHOR]

We report on a method for the measurement of thermal relaxation time constants within light-emitting diodes (LEDs) in the frequency domain. The method is based on the phase shift of the forward voltage waveform with respect to that of the harmonically modulated forward current due to the sensitivity of the forward voltage to junction temperature. The phase shift was shown to exhibit dips at angular frequencies equal to inverse thermal time constants. Extraction of thermal time constants was demonstrated for common low-power and high-power LEDs. The measured thermal time constants (∼0.1–100 ms) were linked to heat flows between the LED components. [ABSTRACT FROM AUTHOR]

The metal gate/high-k dielectric/III-V semiconductor band alignment is one of the most technologically important parameters. We report the band offsets of the Al/Al2O3/GaAs structure and the effect of GaAs surface treatment. The energy barrier at the Al2O3 and sulfur-passivated GaAs interface is found to be 3.0±0.1 eV whereas for the unpassivated or NH4OH-treated GaAs is 3.6 eV. At the Al/Al2O3 interface, all samples yield the same barrier height of 2.9±0.2 eV. With a band gap of 6.4±0.05 eV for Al2O3, the band alignments at both Al2O3 interfaces are established. [ABSTRACT FROM AUTHOR]

Examines the thermoelectric response of normal state YBa[sub 2]Cu[sub 3]O [sub 7] films. Effect of decaying complex and heat diffusion in the response time; Determinants of the decay of the temperature gradient; Existence of anisotropy of the thermopower in the thin films.

Investigates the temperature behavior of indium gallium arsenic phosphide/indium phosphide ridge waveguide structure designed for polarization insensitive semiconductor optical amplifier. Accounts on laser threshold dependence on temperature; Usage of diode structure in the experiment; Discussion on the physical origins of temperature dependence.

Investigates the transition temperature in yttrium-barium-copper-oxygen thin films through low temperature post-annealing. Information on the orthorhombic strain of films; Effects of low temperature post-annealing on coevaporated films; Comparison between the orthorhombic strain of measured thin films and bulk material.

Examines fluorine enhanced oxidation of silicon at low temperatures. Effects of introducing small concentrations of fluorine in the oxygen ambient on oxide growth rate; Information on the presence of fluorine concentration for each oxidation temperature; Determination of fluorine depth in the film.

Investigates the low resistivity of cadmium sulphide (CdS) thin films through chemical bath deposition technique. Contribution of sulphide annealings to the enlargement of CdS cubic cells; Account on hydrogen[sub 2]+indium annealing at higher temperatures; Details on the resistivity of the CdS films at an optimum annealing temperature.

Examines an enhancement of ion-implanted phosphorus activation in silicon through a two-step thermal annealing process. Description of a two-step process; Implication of regrowth process separation from the activation process for electrical activation; Consideration of ion implantation combined with thermal annealing as a standard doping process.

Examines the thermal stability of indium (In)-gallium-arsenic (As) and In-aluminum-As on In-phosphorus strained layers. Analysis on epilayer and interface quality as a function of annealing cycle; Use of high-resolution x-ray diffraction and electron mobility measurements; High crystalline quality retention of pseudomorphic heterostructures.

Examines the thermal stability of Si[sub 1-x]C[sub x]/Si strained layer superlattices grown by molecular beam epitaxy. Use of high resolution x-ray diffraction and secondary ion mass spectroscopy; Employment of different superlattices with alloy compositions; Determination of different pathways to strain relaxation using annealing analysis.

Investigates anomalous temperature dependencies of photoluminescence for visible-light-emitting porous silicon (Si). Use of the electrochemical anodization method at room temperature; Analysis on trends in emission energy shift; Implication for the participation of phonon in the light-emission process of porous Si.

Investigates the atomic layer epitaxy (ALE) of aluminum arsenide using a thermal-cracking tube. Employment of thermally decomposed gas molecules in the analysis; Saturation of AlAs by AsH[sub 3] pulse duration; Adhesion of Al to thermal-cracking tube; Analysis on the cracking kinetics using a quadruple mass spectrometer.

Examines the thermal nitridation of silicon (Si) using an integrated cluster tool process described by the growth of Si[sub 3]N[sub 4] thin films. Effects of thermal nitridation on the core-level Si 2p transition; Observation of a valence-band spectrum; Changes in the thermal Si[sub 3]Ni[sub 4] films caused by dry oxygen molecule exposure.

Investigates the effect of an inhomogeneous stress field on the heat transport of semiconductors. Impact of spatial variations in lattice constants; Diffusion of phonons constituting heat flux at the macroscopic level; Linearity of the change in thermal conductivity with the local stress tensor.

Investigates the temperature dependence of second harmonic generation (SHG) from silicon surfaces. Information on the origin and intensity of the reflected second harmonic signals of silicon surfaces; Explanation for the temperature dependence of the silicon compound; Relevance of SHG to researches on semiconductor surfaces.

Examines the preparation of aluminum oxide thin films on glass and silicon substrates using a low-temperature atmospheric-pressure vapor deposition method. Employment of aluminum acetylacetonate as source material; Measurement of the film composition by photoelectron microscopy; Details on the lowering of substrate temperature.

We investigated how dimensionality affects heat transport in Si-Ge superlattices (SLs) by computing the thermal conductivity of planar superlattices and arrays of Ge nanowires (NWs) and nanodots embedded in Si. We studied superlattices with ∼10 nm periods using a fully atomistic Monte Carlo solution of the Boltzmann transport equation in the relaxation time approximation. We found that for periods larger than 4 nm, the room temperature cross-plane conductivity of planar superlattices with equally thick Si and Ge layers is larger than that of their nanowire and dot counterparts of similar sizes (up to 100%), while the trend is reversed below 4 nm. [ABSTRACT FROM AUTHOR]

Provides a corrected reprint to the article 'Thermal dependence of the refractive index of GaAs and AlAs measured using semiconductor multilayer optical cavities,' published in a 1995 issue of the journal 'Applied Physics Letters.'