Optics of embedded semiconductor nano-objects using a hybrid model: bare versus dressed polarizabilities
Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, 1001 Ta Hsueh Rd., Hsinchu, 300, Taiwan
Corresponding author: a email@example.com
Revised: 2 November 2006
Published online: 22 December 2006
The influence of the surrounding semiconducting matrix upon the optical response of embedded nano-objects (quantum dots) has been investigated. This system can be described by means of a hybrid model, where the full response is a combination of a macroscopic electrostatic response term and a dynamic response term, obtained quantum mechanically. The result is a modified discrete dipole model, where excess discrete dipoles having an excess polarizability with respect to a uniform background identical to the dielectric host material represent the response. In this model all electrodynamic interactions are screened by the host material. The electrostatic response is obtained by approximating the quantum dots by embedded dielectric oblate ellipsoids. Closed expressions for the electrostatic response of these ellipsoids have been derived. The electrodynamic nature of the dynamic quantum mechanical polarizability term however is unclear. It is not certain whether this polarizability is dressed or bare. Therefore we have investigated in detail the consequences of both options. Although there is no real qualitative difference between them, the difference is so large that experiment can easily discriminate between both. Results should be easily measurable anyhow.
PACS: 41.20.Cv – Electrostatics; Poisson and Laplace equations, boundary-value problems / 78.30.Fs – III-V and II-VI semiconductors / 78.67.-n – Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2006