Time-resolved ultrafast carrier dynamics in CdTe quantum dots under high pressure

Ultrafast carrier relaxation in CdTe quantum dots (QDs) was studied under high pressure by using femtosecond transient absorption spectroscopy. The pressure effects on the carrier relaxation time are obtained for surface trapped electron-hole recombination and electronic Auger recombination processes. The decrease of the transient absorption signals and the change of sample colour with pressure are assigned to the shift of the energy levels. This shift of the energy levels can lead to an electron transition for materials. And the abrupt changes of the relaxation time at 0.5 and 1.5 GPa are attributed to the electron transition in CdTe QDs under high pressure. Therefore, the high-pressure ultrafast carrier dynamics research provides a new approach for studying the electron transition in condensed matter. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim