We have developed an atomistic model for dopant diffusion in SiGe structures and we have implemented it in the kinetic Monte Carlo process simulator DADOS. The model takes into account (i) composition and stress effects on the diffusivity of interstitials, vacancies and dopants, (ii) SiGe interdiffusion, (iii) dopant segregation and (iv) the modifications of band-gap and charge levels. The mode...

OBJECTIVE The authors assessed whether brain changes detected by diffusion tensor (DT) MRI can improve the understanding of structural damage in Alzheimer's disease (AD) and are associated with different risks of conversion to AD in amnestic mild cognitive impairment (aMCI). METHODS Twenty-one aMCI patients, 21 AD patients and 20 healthy subjects underwent conventional and DT MRI at baseline....

Electron energy-loss spectroscopy (EELS) in combination with scanning transmission electron microscopy (STEM) reveals that the La enrichment at the surface of cerium-lanthanum solid solutions is an averaged effect and that segregation occurs in a mixed oxide phase. This separation occurs within a crystalline particle, where the dopant-rich phase is located at the surface of the dopant-deficient...

Quantitative ADF-STEM imaging paired with image simulations has proven to be a powerful technique for determining the three dimensional location of substitutionally doped atoms in thin films. Expansion of this technique to lightly-doped nanocrystals requires an understanding of the influence of specimen mistilt on dopant visibility due to the difficulty of accurate orientation determination in ...

We report the study of gold-SrTiO3 (STO)-gold memristors where the doping concentration in STO can be fine-tuned through electric field migration of oxygen vacancies. In this tunnel junction device, the evolution of the density of states (DOS) can be followed continuously across the metal-insulator transition (MIT). At very low dopant concentration, the junction displays characteristic signatur...

This paper presents findings on applying physical models in the literature to describe silicon luminescence spectra at 80 – 300 K. Incorporation of exciton recombination models are shown to disagree with the measured luminescence spectra, whereas a free electron-hole recombination model is shown to match well with the luminescence spectra. However, the lack of consideration for excitons is not ...

Semiconductor devices have been scaled to the point that transport can be dominated by only a single dopant atom. As a result, in a Si fin-type field effect transistor Kondo physics can govern transport when one electron is bound to the single dopant. Orbital (valley) degrees of freedom, apart from the standard spin, strongly modify the Kondo effect in such systems. Owing to the small size and ...

We present the first realization of three-dimensional lithography on the nanometer scale using atom optical techniques. It has already been shown that, with atom lithography, two-dimensional lateral structures of 50 nm can be obtained. In our experiment we utilize the resonant enhancement of light forces to address specifically one species of a multi-component beam. Thus a host and a dopant mat...

We present the first experimental results of the studying of field electron emission from sharp silicon tips covered by thin dielectric CaF2 layers containing Sm dopant ions. Some indications on the resonant tunneling of electrons from sharp silicon tip through dopant samarium ions inside the coating have been observed, which can be regarded as an implementation of one-atom electron source of a...

Copper(II)-doped Pb[Zr0.54Ti0.46]O3 (PZT) ferroelectrics with a dopant concentration of 0.25 mol % were investigated at high magnetic fields, enabling an enhanced resolution of the structural distortion at the dopant site. The results obtained suggest that Cu2+ substitutes as an acceptor centre for [Zr,Ti]4+ in oxygen octahedra with tetragonal, monoclinic and rhombohedral distortion, confirming...