Excitons in spherical quantum dots revisited: analysis of colloidal nanocrystals
- PDF / 949,691 Bytes
- 9 Pages / 595.276 x 785.197 pts Page_size
- 89 Downloads / 300 Views
THE EUROPEAN PHYSICAL JOURNAL B
Regular Article
Excitons in spherical quantum dots revisited: analysis of colloidal nanocrystals R.L. Restrepo 1,a , Walter Antonio Ospina-Mu˜ noz 1 , E. Feddi 2 , M.E. Mora-Ramos 3 , J.A. Vinasco 4 , 4 4 A.L. Morales , and C.A. Duque 1 2
3
4
Universidad EIA, CP 055428, Envigado, Colombia Group of Optoelectronic of Semiconductors and Nanomaterials, ENSET, Mohammed V University in Rabat, Rabat, Morocco Centro de Investigaci´ on en Ciencias, Instituto de Investigaci´ on en Ciencias B´ asicas y Aplicadas, Universidad Aut´ onoma del Estado de Morelos, Av. Universidad 1001, CP 62209, Cuernavaca, Morelos, Mexico Grupo de Materia Condensada-UdeA, Instituto de F´ısica, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medell´ın, Colombia Received 12 February 2020 / Received in final form 7 April 2020 Published online 15 June 2020 c EDP Sciences / Societ`
a Italiana di Fisica / Springer-Verlag GmbH Germany, part of Springer Nature, 2020 Abstract. The problem of exciton states in spherical semiconductor quantum dots is revisited, employing the finite element method to numerically solve the system of differential equations for the center of mass and relative motion of the interacting electron-hole pair. This process is performed within the effective mass and parabolic bands approximations. The use of a finite confinement together with a parabolic description of the conduction and valence band profiles prevents the two equations from uncoupling. The allowed energies are reported as functions of the quantum dot radius. A comparison of theoretically determined fundamental photoluminescence peak energies with available experimental reports in the cases of CdS, CdSe and CdTe is presented and discussed, showing a good agreement between calculated and measured results.
1 Introduction Semiconducting nanosystems exhibit standalone physical properties which pose the possibility of a broad variety of applications in optics and electronics. Hence, researchers have made a great deal of effort to understand them, with the aim to pointing those of fundamental and practical relevance. From basic solid state physics, it is known that excitons play a key role in the optical response of nonmetallic materials. In the case of semiconductor heterostructures, the description of these correlated electron-hole pair in quantum wells (QW) can be traced from the pioneering work by Bastard et al. [1], to – for instance – the most recent approach by Belov [2]. In the former, the authors make use of the variational method to calculate the ground state exciton binding energy. Such approach has remained as the most widely employed when investigating exciton properties and related photoluminescence peak (PL-peak) experiments [3–5]. On the other hand, the work by Belov [2] puts forward a treatment of the coupled electron-hole phenomenon by means of a numerical solution of the exciton within the effective mass approximation, using finite a
e-mail: [email protected]
dif
Data Loading...
