Phys. Rev. B 75, 075325 (2007) - Frequency degenerate and nondegenerate two-photon absorption spectra of semiconductor quantum dots

Frequency degenerate and nondegenerate two-photon absorption spectra of semiconductor quantum dots

L. A. Padilha, J. Fu, D. J. Hagan, E. W. Van Stryland, C. L. Cesar, L. C. Barbosa, C. H. B. Cruz, D. Buso, and A. Martucci

Phys. Rev. B 75, 075325 – Published 20 February 2007

Abstract

The frequency degenerate and nondegenerate two-photon absorption (2PA) spectra of direct band gap semiconductor quantum dots are studied. Measuring the spectra for both cases in samples of CdSe and CdTe with different quantum dot sizes and size distributions, we observe that the 2PA spectra and the 2PA coefficient are size dependent, so that smaller dots have smaller 2PA even after taking into account the volume fraction. Theory considering the mixing of the hole bands, in a $\vec{k} ∙ \vec{p}$ model, explains the data quite well except for the smallest dots. A comparison with the parabolic band approximation is also shown.

Received 25 August 2006

DOI:https://doi.org/10.1103/PhysRevB.75.075325

©2007 American Physical Society

Authors & Affiliations

L. A. Padilha², J. Fu, D. J. Hagan^*, and E. W. Van Stryland^*

College of Optics & Photonics: CREOL & FPCE, University of Central Florida, 4000 Central Florida Blvd., Orlando, Florida 32816-2700, USA

C. L. Cesar, L. C. Barbosa, and C. H. B. Cruz

Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas (UNICAMP), 13083-970, Campinas, São Paulo, Brazil

D. Buso and A. Martucci

Dipartimento di Ingegneria Meccanica—Settore Materiali, Universitá di Padova, via Marzolo, 9, I-35131 Padova, Italy

^*Also with the Physics Department.

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Issue

Vol. 75, Iss. 7 — 15 February 2007

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