Increasing temperature is known to quench the excitonic emission of bulk silicon,which is due to thermally induced dissociation of excitons.Here,we demonstrate that the effect of temperature on the excitonic emission ...Increasing temperature is known to quench the excitonic emission of bulk silicon,which is due to thermally induced dissociation of excitons.Here,we demonstrate that the effect of temperature on the excitonic emission is reversed for quantumconfined silicon nanocrystals.Using laser-induced heating of silicon nanocrystals embedded in SiO2,we achieved a more than threefold(4300%)increase in the radiative(photon)emission rate.We theoretically modeled the observed enhancement in terms of the thermally stimulated effect,taking into account the massive phonon production under intense illumination.These results elucidate one more important advantage of silicon nanostructures,illustrating that their optical properties can be influenced by temperature.They also provide an important insight into the mechanisms of energy conversion and dissipation in ensembles of silicon nanocrystals in solid matrices.In practice,the radiative rate enhancement under strong continuous wave optical pumping is relevant for the possible application of silicon nanocrystals for spectral conversion layers in concentrator photovoltaics.展开更多
基金supported by the Dutch Technology Foundation STW,which is part of the Netherlands Organisation for Scientific Research(NWO)funded by the Ministry of Economic Affairs+1 种基金support within the framework of the Czech-German collaborative project,16-09745J(DFT-GACR)supported by the Russian Science Foundation,Grant No.14-12-01067。
文摘Increasing temperature is known to quench the excitonic emission of bulk silicon,which is due to thermally induced dissociation of excitons.Here,we demonstrate that the effect of temperature on the excitonic emission is reversed for quantumconfined silicon nanocrystals.Using laser-induced heating of silicon nanocrystals embedded in SiO2,we achieved a more than threefold(4300%)increase in the radiative(photon)emission rate.We theoretically modeled the observed enhancement in terms of the thermally stimulated effect,taking into account the massive phonon production under intense illumination.These results elucidate one more important advantage of silicon nanostructures,illustrating that their optical properties can be influenced by temperature.They also provide an important insight into the mechanisms of energy conversion and dissipation in ensembles of silicon nanocrystals in solid matrices.In practice,the radiative rate enhancement under strong continuous wave optical pumping is relevant for the possible application of silicon nanocrystals for spectral conversion layers in concentrator photovoltaics.
