We study the changes of magnetoresistance induced by controlled thermal annealing at temperatures ranging from 300 to 600 °C of a Ga0.98Mn0.02As alloy grown by low-temperature molecular beam epitaxy. We use a resistor-network model for describing the electrical transport as a function of temperature and external magnetic field. The model is founded on classical semiconductor band transport and ...

Multiband solar cells are one type of third generation photovoltaic devices in which an increase of the power conversion efficiency is achieved through the absorption of low energy photons while preserving a large band gap that determines the open circuit voltage. The ability to absorb photons from different parts of the solar spectrum originates from the presence of an intermediate energy band...

An antitrapping current scheme for quantitative phase-field model [A. Karma, Phys. Rev. Lett. 87, 115701 (2001)] is extended to solidification process in a dilute binary alloy system involving diffusion in the solid. It is demonstrated in an asymptotic analysis that in the case of an arbitrary value of the solid diffusivity, five types of constraints exist between interpolating functions used i...

The growth and phase segregation properties of the potential dilute magnetic semiconductor alloy, (MnSe)x(Ga2/3Se)1−x, are studied as a function of thickness, Mn concentration, post-growth annealing, and the presence or absence of undoped Ga2Se3 buffer and capping layers. This system is an unusual case in heteroepitaxy where two phase MnSe+Ga2Se3 has better lattice matching than the (MnSe)x(Ga2...

We present results from direct numerical simulations of two types of technologically important phase change processes: directional solidification of a binary alloy and film boiling. We use a two-dimensional finite-difference/front-tracking method which allows us to accurately follow the evolution of the interface between the phases. The method is general in the sense that discontinuities in mat...

The effect of substituting 0.01 at.% Er for Sc in an Al–0.06Zr–0.06Sc–0.04Si (at.%) alloy subjected to a two-stage aging treatment (4 h/300 C and 8 h/425 C) is assessed to determine the viability of dilute Al–Si–Zr–Sc–Er alloys for creep applications. Upon aging, coherent, 2–3 nm radius, L12-ordered, trialuminide precipitates are created, consisting of an Erand Sc-enriched core and a Zr-enriche...

In this work, the evolution of microstructure and the thermo-mechanical behavior of co pper and dilute copper alloy thin films was investigated. 0.3 to 2.0 μm thick film s were deposited by magnetron sputtering under ultra high vacuum conditions onto diffusion-barrier coated silicon substrates and subjected to wafer curvature measurements. Pure copper films annealed in ultra high vacuum exhibit...

Fully strained single-crystal metastable Ge1−xSnx layers were grown on Ges001d in order to probe the role of Sn dopant and alloy concentrations sCSn=1310 cm−3 to 6.1 at. % d on surface roughening pathways leading to epitaxial breakdown during low-temperature s155 °Cd molecular-beam epitaxy of compressively strained films. The addition of Sn was found to mediate Ges001d surface morphological evo...

Tailoring recrystallization via particle-stimulated nucleation (PSN) and pinning effects from secondary phase particles effectively weakens textures, which is still challenging for low-alloyed rare earth-free Mg alloys. Herein, the texture of a dilute cold-rolled Mg-2.2Al-0.33Ca (wt.%) alloy found to reduce with appearance transverse direction (TD) components during static recrystallization. Th...

The supercell approach to defects and alloys has circumvented the limitations of those methods that insist on using artificially high symmetry, yet this step usually comes at the cost of abandoning the language of E versus k band dispersion. Here we describe a computational method that maps the energy eigenvalues obtained from large supercell calculations into an effective band structure (EBS) ...