Eur. Phys. J. B 65, 505-509 (2008)
https://doi.org/10.1140/epjb/e2008-00357-8

Coulomb-induced nonlinearities in GaN microdisks

¹ Photonics-Electronics Division, Research Institute for Applied Physics and Astronomy (RIAPA), University of Tabriz, 51665-163, Tabriz, Iran
² Istituto Nazionale per la Fisica della Materia (INFM) and Dipartimento di Fisica, Università degli Studi di Modena e Reggio Emilia, Via Campi 213/A, 41100 Modena, Italy

Corresponding author: ^a saeid.shojaei@unimore.it

Received: 3 July 2008
Revised: 23 July 2008
Published online: 25 September 2008

Abstract

Due to their wurzite structure, GaN quantum wells and dots are characterized by large built-in piezoelectric fields. These induce a spatial separation between the confined electron and holes, thus favouring the formation of electric dipoles. Here, we theoretically investigate the effects of the long-range, dipole-dipole interaction between two excitons in a GaN/Al_xGa_1-xN microdisk. These Coulomb interactions are shown to strongly affect the biexciton ground state. In particular, they induce strong spatial correlations between the two excitons and result in biexciton binding energies of the order of 1 meV.