Carrier Multiplication in Silicon Nanocrystals: Theoretical Methodologies and Role of the Passivation

Carrier multiplication is a non-radiative recombination mechanism that leads to the generation of two or more electron-hole pairs after absorption of a single photon. By reducing the occurrence of dissipative effects, this process can be exploited to increase solar cell performance. In this work, we introduce two different theoretical fully ab initio tools that can be adopted to study carrier multiplication in nanocrystals. The tools are described in detail and compared. Subsequently, we calculate carrier multiplication lifetimes in H- and OH-terminated silicon nanocrystals, pointed out the role played by the passivation on the carrier multiplication processes.