2007/07/13 by Rupasov, Valery I., Klimov, Victor I.
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Other Condensed Matter (cond-mat.other)
paper · doi:10.48550/arxiv.0707.2112
We propose a novel mechanism for photogeneration of multiexcitons by single photons (carrier multiplication) in semiconductor nanocrystals. In this mechanism, the Coulomb interaction between two valence-band electrons involving their transfer to the conduction band creates a virtual biexciton from vacuum that is then converted into a real biexciton by photon absorption on an intraband optical transition. This mechanism is inactive in bulk semiconductors as momentum conservation suppresses intraband absorption. However, it becomes highly efficient in zero-dimensional nanocrystals and can provide a significant contribution to carrier multiplication in these materials.