Eur. Phys. J. B 84, 431-438 (2011)
https://doi.org/10.1140/epjb/e2011-20466-5

Regular Article

Optical absorption and refraction index change of a confined exciton in a spherical quantum dot nanostructure

¹ Department of Physics, St. Michael College of Engg. & Tech, 630551 kalaiyarkoil, India
² Department of Physics, Govt. Arts College, 625106 Melur, Madurai, India
³ Department of Chemical Engineering and Green Energy Center, College of Engineering, Kyung Hee University, 1 Seochun, Gihung, Yongin, 446-701 Gyeonggi, S. Korea

^a e-mail: a.john.peter@gmail.com

Received: 14 June 2011
Received in final form: 11 October 2011
Published online: 23 November 2011

Abstract

Electronic energies of an exciton confined in a strained Zn_1−xCd_xSe/ZnSe quantum dot have been computed as a function of dot radius with various Cd content. Calculations have been performed using Bessel function as an orthonormal basis for different confinement potentials of barrier height considering the internal electric field induced by the spontaneous and piezoelectric polarizations. The optical absorption coefficients and the refractive index changes between the ground state (L = 0) and the first excited state (L = 1) are investigated. It is found that the optical properties in the strained ZnCdSe/ZnSe quantum dot are strongly affected by the confinement potentials and the dot radii. The intensity of the total absorption spectra increases for the transition between higher levels. The obtained optical nonlinearity brings out the fact that it should be considered in calculating the optical properties in low dimensional semiconductors especially in quantum dots.