We will discuss the advantages of the realization of SiC/SiO<sub>2</sub> quantum structures and their optical absorption properties. Our calculations suggest that it is possible to extend the range of the optical absorption of such structures to build applications that operates from infrared to UV spectrum using a single material and band-structure engineering.
In this work, we will discuss Si-/SiGe and high-κ oxides nanostructures. The exciton properties of strained Si/Si<sub>1-χ</sub>Ge<sub>χ</sub> quantum well (QW) are calculated taking into account interface effects and both possibilities of the band lineup of the conduction-band offset, type-I and type-II. Our
numerical results show that interface fluctuations of only 10 Å in a Si/Si<sub>1-χ</sub>Ge<sub>χ</sub> 50 Å type-I QW (type-II QW) leads to a 25 meV (10 meV) blueshift of the exciton (transition) energy. Concerning high- κ nanostructures, our simulation was performed in order to analyse how the charge image effects can modify the electronics properties in Si/HfO<sub>2</sub> and Si/SrTiO<sub>3</sub> based quantum wells. The results of Si/SrTiO<sub>3</sub> (Si/HfO<sub>2</sub>) quantum wells indicate a recombination emission difference, as compared with the case when no charge image effects are included, of the order of 1.5 eV (0.7 eV).
The consequences of the use of high-k dielectrics in nanocrystal based non-volatile flash memories focusing on the electrical and electronic properties are investigated through computational simulations. In the light of these results, we discuss several aspects which must be addressed for the design of such devices. We focus on nanocrystals flash memories with HfO<sub>2</sub> and SiO<sub>2</sub> for analysis. Due to significant reductions of the single-electron tunneling time and improvements on the data retention, high-k dielectrics offers important improvements for the non-volatile flash memories technology.