Ab initio studies of the optoelectronic structure of undoped and doped silicon nanocrystals and nanowires: the role of size, passivation, symmetry and phase

Abstract

Results from ab initio calculations for singly- and co- doped Si nanocrystals and nanowires are presented.

Multiple exciton generation in isolated and interacting silicon nanocrystals

“…176 As discussed in section 2.2, another possibility to reduce the energy gap of Si NCs is given by B and P co-doping. As proved by ab initio calculations, 3,4,166,[177][178][179][180] and as confirmed by experimental activities, 164,165,168,181 compensated co-doping leads to minor structural distortions around the impurities and is energetically favored over single doping. Moreover, the presence of both P and B dopants leads to the formation of impurity-related energy states in the bandgap with a consequent reduction of the energy gap (which can settle to values <1 eV) with respect to the undoped systems.…”

“…Again, the interplay between nanocrystals (NCs) can be used to modify the excited state manifold of the systems (and therefore their absorption and emission properties) and to promote charge and energy transfer processes between nanostructures. [1][2][3][4] Finally, nanostructured materials can be easily integrated into existing solar cell schemes, thus offering novel physical and chemical properties for high-performance photovoltaic platforms.…”

Origin and Quantitative Description of the NESSIAS Effect at Si Nanostructures

“…[1][2][3] To this end, the structures under investigation have to be in the range of the NESSIAS impact length. Many published Density Functional Theory (DFT) calculations [6][7][8][9] lack an energy assignment on an absolute scale. Possibly identical low nanoscale intrinsic Si NWell systems near the low end of the one-digit nm range embedded in different dielectrics pose a challenge in experiment.…”