The optical properties of GaAs nano-wires grown on shallow-trench-patterned Si(001) substrates were investigated by cathodoluminescence. The results showed that when the trench width ranges from 80 to 100 nm, the emission efficiency of GaAs can be enhanced and is stronger than that of a homogeneously grown epilayer. The suppression of non-radiative centers is attributed to the trapping of both ...

Barrier layer material deposited on stainless steel substrate has been under investigation. These layers are part of a film-Si module, presently under development at ECN. Low temperature (< 250°C) processing is required in order to avoid impurity diffusion from the stainless steel foil. Novel materials based on nano particles combined with organic/ inorganic polymers and SiOx precipitated from ...

X-ray standing waves ~XSW! and grazing incidence x-ray diffraction ~GIXD! were used to investigate the crystallinity of ultrathin Ge films grown by molecular-beam epitaxy on Si~001! with and without Te as a surfactant. The Ge layer thickness ranged from 1 to 10 ML. The results clearly indicate that Ge films grown with Te have a higher degree of crystallinity compared to those grown without Te. ...

In the field of nanoscale magnetocaloric materials, novel concepts like micro-refrigerators, thermal switches, microfluidic pumps, energy harvesting devices and biomedical applications have been proposed. However, reports on (Mn,Fe)2(P,Si)-based which are one most promising bulk materials for solid-state magnetic refrigeration, rare. this study we synthesized nanoparticles, systematically inves...

This work presents a comprehensive analysis of the SiGe band structure using a TightBinding based approach within the virtual crystal approximation. We analyze the material properties of bulk relaxed SiGe and biaxially compressed strained systems. The simulation approach has been benchmarked against experimental data wherever possible. We further investigate the effect of process induced uniaxi...

Transistor designs based on using mixed -L valleys for electron transport are proposed to overcome the density of states bottleneck while maintaining high injection velocities. Using a self-consistent top-of-the-barrier transport model, improved current density over Si is demonstrated in GaAs/AlAsSb, GaSb/AlAsSb, and Ge-on-insulator-based singlegate thin-body n-channel metal–oxide–semiconductor...

By combining Raman scattering from the cleaved edge and under hydrostatic pressure, we have accurately determined the tetragonal phonon deformation potentials of strained Si1−xGex alloys in the entire compositional range for the Ge-like, Si-like, and mixed Si–Ge optical modes. A known biaxial strain is induced on thin alloy layers by pseudomorphic epitaxial growth on silicon and subsequent capp...

Interfacial topological states are a key element of interest for topological insulator thin films, and their properties can depend sensitively on the atomic bonding configuration. We employ in situ nonresonant and resonant surface x-ray scattering to study the interfacial and internal structure of a prototypical topological film system: Bi2Te3 grown on Si(111). The results reveal a Te-dominated...

In this thesis, I present a theoretical model for the Si core/SiGe shell core-shell nanowire system. A model for the single carrier pocket core-shell nanowire is first developed, along with the boundary conditions of a circular wire and sharp interfaces between the two media. A numerical scheme is then developed for the core-shell nanowire system, along with educated approximations for the nume...