Auger recombination and intraband absorption of two-photon-excited carriers in colloidal CdSe quantum dots

Auger recombination, quantized Auger rate, and intraband absorption of two-photon-excited carriers in colloidal CdSe quantum dots have been investigated systematically with femtosecond Z scans and transient absorption measurements. The Auger constant is revealed to be on the order of 10−30cm6s−1, while the intraband absorption cross sections are found to be in the range of 10−18–10−17cm2. The authors’ experimental evidence demonstrates that the Auger recombination or the intraband absorption takes place under the condition that the average electron-hole pair per quantum dot is in excess of the unity.