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

TL;DR

This paper introduces two ab-initio theoretical tools to study carrier multiplication in silicon nanocrystals, highlighting how passivation influences the process and potentially improving solar cell efficiency.

Contribution

The work presents novel fully ab-initio methodologies for analyzing carrier multiplication and compares their effectiveness in silicon nanocrystals with different passivation.

Findings

Passivation significantly affects carrier multiplication lifetimes.

Two ab-initio tools are detailed and compared for studying nanocrystals.

Carrier multiplication can be optimized for solar cell applications.

Abstract

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.