Unlike to III-V quantum dots, Si-nanocrystals (Si-ncs), because of their large intrinsic linewidths are not considered to be suitable emitters for emission rate enhancement observations (Purcell effect). Here, we report on direct measurements of spontaneous emission rate enhancement of Si-ncs embedded in a whispering-gallery mode (WGM) resonator at room temperature . Optically active microdisk resonators have been fabricated and characterized through single-disk time-resolved micro-photoluminescence (PL) experiments. We demonstrate experimentally that the emission lifetime of Si-ncs coupled to WGM cavity resonances is reduced by up to ~70% with respect to uncoupled ones. Comparing our experimental results with theoretically predicted Purcell enhancement in a bad emitter regime, we estimate effective linewidths of 10meV through which Si-nc emitters are coupled to WGM cavity photons. Finally, our study provides an alternative method for the estimation of sub-natural linewidths of quantum dots at room temperature.
File in questo prodotto:
Non ci sono file associati a questo prodotto.