Estudio del transporte y absorción de luz en redes periódicas de puntos cuánticos de semiconductor

Resumo

In this work we present a study on the features of electron transport and photon absorption in quantum dot arrays. We developed theoretical models and implemented a simulator to assess the viability of semiconductor colloidal quantum dot arrays as solar cell active components. To this end, we have focused our study on the calculation of the miniband structure, carrier mobility and photon absorption coefficient. In this thesis we investigated carrier transport in quantum dot superlattices, a kind of highly ordered systems. Transport in these systems have been widely studied using hopping models. These approaches seem to be adequate for disordered and diluted systems, where quantum dot eigenstates overlap weakly and with no periodicity with other neighboring quantum dot. As the state of the art continues to advance towards higher quality, better ordered quantum dot arrays, experimental results report data evidencing band-like transport features. In this thesis we propose a novel picture helping to understand carrier transport in these systems, combining impurity scattering effects with the carrier ensemble thermalization through phonon scattering contribution. Regarding photon absorption, we mainly focused on studying the inuence of quantum dot material, size and interdot distance in the absorption in twodimensional arrays. We carried out a deep analysis on the inuence of light polarization, Fermi level position and temperature in the system. We developed this study with the aim of proposing several strategies focused on finding applications on intermediate band solar cells. Finally a set of unpublished results are presented on this topic for finite systems.