Three-photon absorption in semiconductor quantum dots: experiment.
The four-band model, derived under the effective-mass approximation for cubic semiconductor quantum dots (QDs), is compared with experimental measurements on frequency degenerate three-photon absorption (3PA) in CdSe QDs and ZnS QDs. Qualitatively, the model provides the correct prediction on the magnitude of the 3PA cross-sections, which are in the range from 10(-79) to 10(-77) cm(6)s(2)photon(-2) in the light frequency region of interest. More noticeably, the theoretical conclusion of an increasing tendency in the 3PA cross-sections with increasing dot-size is in agreement with the experiment. The discrepancy is also found for smaller QDs (dot-radius is less than one-third of the exciton Bohr radius), which is attributed to neglecting the mixing among the three valence bands in the theory.
Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore.
Xiaobo
X
Feng
Yu Long
YL
Ang
Jun
J
He
Cyrus W J
CW
Beh
Hairu
H
Xu
Wee Shong
WS
Chin
Wei
W
Ji
D000042:Absorption; D019187:Cadmium Compounds / Q000737:chemistry; D003460:Crystallization; D008027:Light; D015233:Models, Statistical; D053758:Nanoparticles; D036103:Nanotechnology / Q000379:methods*; D010777:Photochemistry / Q000379:methods; D017785:Photons; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry; D012666:Semiconductors; D013053:Spectrophotometry / Q000379:methods; D013440:Sulfides / Q000737:chemistry; D013696:Temperature; D017967:Zinc Compounds / Q000737:chemistry
D019187:Cadmium Compounds; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; C058667:cadmium selenide; C031238:zinc sulfide