Nonlinear optical spectroscopy of cadmium chalcogenide nanocrystals.
by Seo, J. T.; Yang, Q.; Creekmore, S.; Mangana, J.; Anderson, J.; Pompey, C.; Temple, D.; Peng, X.; Qu, J. L.; Yu, W.; Wang, A.; Jung, S.; Ruh, H.; Mott, A.; Namkung, M.
The authors report on the nonlinear optical properties of Cd telluride (CdTe) semiconductor colloidal quantum dots. TEM measurements revealed that the size of CdTe nanocrystal quantum dots, dependent on the growth reaction time, was ~2-10 nm or near the exciton Bohr radius. The strong blue-shifts of the CdTe, CdSe and CdS nanocrystal absorption spectra and the at.-like discrete energy states of exciton indicate an exciton quantum confinement. These are completely different optical properties from the bulk crystals. The energy transition for exciton absorption was assigned as h1-?e+, h2-?e+, h1+?e-, and h2+?e- for the 1st, 2nd, 3rd and 4th exciton absorption peaks. Z-scan and I-scan nonlinear spectroscopy revealed that the CdTe nanocrystal quantum dot in toluene (~8 × 10-5 mol/L) has the neg. nonlinearity (self-defocusing) with approx. -1 × 10-13 m2/W and a high nonlinear figure of merit of ~200. For the optical power self-limiting experiment, the CdTe nanocrystal was almost opaque ?0.8 MW/cm2 at the position of z ~ 6.9 cm.
- Journal
- Materials Research Society Symposium Proceedings
- Volume
- 780
- Year
- 2003
- Start Page
- 87-92
- URL
- https://dx.doi.org/10.1557/proc-780-y3.1
- ISBN/ISSN
- 0272-9172
- DOI
- 10.1557/proc-780-y3.1