Influence of AlN/GaN interfacial non-idealities on the properties of two-dimensional electron gas in AlGaN/AlN/GaN heterostructures

The influence of two types of AlN/GaN interfacial non-idealities, namely unintentional Ga incorporation into AlN spacer and blurring of the spacer due to Al and/or Ga atomic diffusion on the mobility and density of two-dimensional electron gas in AlGaN/AlN/GaN heterostructure was studied theoretically. It was found that moderate amount of GaN in the nominal AlN spacer does not affect much the mobility and density of 2DEG as long as the interface is abrupt. In contrast, the blurring of AlN/GaN interface was found to have a significant impact on the mobility and sheet resistance of the structure since the GaN channel actually becomes AlGaN and alloy-disorder scattering takes place.

Ensemble Monte Carlo Simulation of Hole Transport in SiGe Alloys

This paper employs Ensemble Monte Carlo method to simulate transport of holes in SiGe alloys. A three-band model was employed to describe the valence band of these alloys. The nonparabolicity and the warping effect of the heavy-hole and light-hole bands were considered in their dispersion relation, while the split-off band was described as parabolic and spherical. We consider phonon and alloy disorder scattering in these calculations. The mobility of holes for a range of SiGe al-loys was calculated at 300K. The simulation mobility results agree with the experimental data, implying that the selected transport model for holes in SiGe alloys is adequate.

Temperature-dependent electrical resistivity and magnetoresistance characteristics of Zn1−xVxO thin films above Mott critical density

Temperature-dependent (5–200 K) electrical resistivity and magnetoresistance (MR) measurements were carried out on [Formula: see text] (x = 0.5–4 at.%) thin films grown by pulsed laser deposition (PLD). The free electron concentration in the films was found to be in the range of [Formula: see text](1.7–4.7) [Formula: see text] which is much higher compared to the Mott critical density required for the onset of insulator-to-metal transition in ZnO. All the films exhibited small negative MR in the entire temperature and magnetic field range indicating weak-localization as the dominant effect. However, some unusual MR behavior was observed at 5 K for the film with highest static-disorder parameter. Such characteristics have been well-explained by considering the interplay of negative MR (arising due weak-localization and spin-disorder scattering) and positive MR (caused by s–d exchange interaction induced spin-splitting of the conduction band).

Vacancy and anti-site disorder scattering in AgBiSe2 thermoelectrics

Ag vacancies in AgBiSe2 influence Ag–Bi anti-site disorder and provide point defect scattering, reducing the lattice thermal conductivity.

Structural and Transport Properties of Ni45Mn40In15 Thin Films

We report on structural and transport properties of Ni-Mn-In thin films. The results obtained have indicated that transport properties of the thin films strongly depend on the structural ordering of the films. Specifically, annealing converts the semiconducting-like character of the resistivity into that typical for metals. This is due to annealing-induced crystallization of as-deposited films which are in partially amorphous state. In both the as-deposited and the annealed thin films the field dependence of the resistivity is negative, which is typical for thin films of Heusler alloys and can be ascribed to the suppression of the spin disorder scattering.