Silicon-Based Third Generation Photovoltaics

Optimization of Third Generation Nanostructured Silicon- Based Solar Cells

“…As long as Si QDs or clusters of Si QDs are small enough, they "keep" the carrier that resides in them and become charged when an excess charge carrier reaches them. Hence, the transport through the system can take place only if a corresponding charging (or Coulomb) energy is provided [15]. Balberg et al in 2004 reported this topic for the samples with low number of Si QDs in the ensemble, which are characterized by the QDs of regime 1, the local conductivity is determined by the tunneling of charge carriers under Coulomb blockage between adjacent nanocrystallites similar to the case encountered in granular metals in the dielectric regime.…”

“…The transport properties of the ensembles of disordered Si QDs in insulating matrix could be explained in terms of the percolation theory, which has already been successfully implemented to explain the transport processes in granular metals by Abeles et al in 1975. Indeed, this theory describes the effect of the system's connectivity on its geometrical and physical properties [15].…”

“…Si ion implantation into an oxide layer can be used to produce Si QDs at an irregular position with a relatively large size distribution. Si QDs can fabricate by solution synthesis, mechanical milling, and particle selection from porous silicon, but it is difficult to control the size uniformity of distributed QDs or an additional process to select the particle with the same size [15].…”

“…HRTEM images of the ensembles of Si QDs corresponding to different structuralelectrical regimes: (a) uniformly dispersed isolated spherical QDs (regime 1), (b) clusters of "touching" QDs (regime 3) and (c) percolation clusters of "touching" QDs (regime 5)[15].…”