Optics and Photonics Society of Iran

One of the approaches to increase the efficiency of solar cell devices based on semiconductor nanostructures is to use multiple exciton generation (MEG) process, that in certain circumstances, several excitons are generated by the absorption of a single photon. In this paper, we obtain and compare multiple exciton generation in silicon and germanium nanocrystals. Our results with EOM-CCSD method show that MEG process in germanium nanocrystal around 0.8 eV starts earlier than silicon nanocrystal, and its threshold is around 8% lower. The calculated MEG threshold is based on optical bandgap and our results are consistent with experimental reports.