Carrier Multiplication in CdTe Quantum Dots by Single-photon Timing Spectroscopy

Abstract
Carrier multiplication (CM) was observed in CdTe quantum dots (QDs) capped with tetradecylphosphonic acid (TDPA) at hν⁄Eg>2.5 by picosecond single-photon timing spectroscopy, where hν and Eg are the excitation and the band gap energies, and the CM efficiency increased rapidly with the increase of hν⁄Eg. No CM was observed less than the threshold value of hν⁄Eg≈2.5, which is close to that of CdSe QDs. As compared to a previous report by Nair and Bawendi, our result suggests that CM is sensitive to the QD surface conditions.
Keywords