Microscopic and Macroscopic Bipolar Injection and Carrier Recombination in Single-layer Si Nanocrystals

摘要

Si nanocrystals(NCs)based optoelectronic devices have attracted more and more attentions due to the quasi-direct energy band structure and the adjustable band gap of Si NCs.In these optoelectronic devices,the carrier injection and recombination process is a crucial issue and needs to be deeply understood.Here,bipolar carrier injection and recombination process in a single layer of Si NCs was observed at the microscopic and macroscopic scales,by electrostatic force microscopy(EFM)and alternating-current electroluminescence(ac EL)measurement,respectively.EFM result showed that opposite charges could be injected into the single-layer Si NCs and they would laterally recombine with each other.On the other hand,the single-layer Si NCs also showed a frequency dependent EL intensity,which was attributed to the time limitation of carrier injection and radiative recombination process.