The equilibrium geometries, phonon spectra, electronic structures and optical properties of the Ci Oi defect in bulk Si and Si1−x Gex systems are calculated using the ab initio plane wave density-functional method. We find that in a Gedoped Si crystal it is more energetically favourable for the defect to stabilize in a configuration with no Ge atoms in the first sphere. Our calculations show th...

Solar cells that convert sunlight into electrical energy are the main component of a solar power system. Quality inspection of solar cells ensures high energy conversion efficiency of the product. The surface of a multi-crystal solar wafer shows multiple crystal grains of random shapes and sizes. It creates an inhomogeneous texture in the surface, and makes the defect inspection task extremely ...

In silicon processing technology one of the most important current objectives is to achieve a controlled impurity doping in the crystal. Point defects and defect complexes present in the crystal influence in an important way the electrical activity and the diffusion properties of the dopants. In this thesis, defect complexes in silicon are studied by using quantum-mechanical electronic-structur...

This paper presents a generalization of traditional continuum approaches to liquid crystals and liquid crystal elastomers to allow for dynamically evolving line defect distributions. In analogy with recent mesoscale models of dislocations, we introduce fields that represent defects in orientational and positional order through the incompatibility of the director and deformation ‘gradient’ field...

patients and methods previously recorded data of 231 patients who underwent surgical closure of vsd between january 2009 and january 2012 at the rajaie cardiovascular medical and research center were retrospectively reviewed. vsd surgical repair was performed using continues suturing technique in group a patients (n = 163, 70.6%) and interrupted suturing technique in group b patients (n = 68, 2...

Existing investigations on imperfect phononic crystal beams mainly concern periodic multi-span beams carrying either one or two channel waves with random or deterministic disorder in span-length. This paper studies the two channel bending waves in phononic crystal beams consisting of many phases of materials with defects introduced as one structural segment having different cross-sectional dime...

The quality of crystalline silicon highly influences the quality of semiconductor devices fabricated with it. Grown-in defects, such as octahedral voids or networks of large dislocation loops can be detrimental to the functionality of devices. Both type of defects result from the interaction of intrinsic point defects, vacancies and self-interstitials during growth and subsequent annealing of t...

Spontaneous symmetry breaking while preserving flow ability is a remarkable feature of nematic liquid crystals. When a nematic liquid crystal coexists with a solid, the surface field of the solid tends to anchor the director direction on the surface: anchoring effects. If geometrical frustration between nematic ordering and anchoring is strong enough, stable topological defects are formed. Defe...