EFFECT OF THE STARK CONFINEMENT ON THE EXCITONIC OPTICAL-SPECTRUM OF AN ARRAY OF COUPLED QUANTUM DOTS

We investigate theoretically the influence of a uniform electric field on the optical properties of a linear array of coupled quantum dots. We study the excitonic spectrum of this system by solving the electron -hole effective-mass Hamiltonian. The potential along the array is mod eled by a periodic square-well potential and we assume parabolic later al confining potentials for electrons and holes. We calculate the exci tonic absorption coefficient as a function of the quantum dot size and the applied electric field. We discuss the different confinement regi mes. The results illustrate the competing effects of the lateral confi nement, the electric-field confinement, and the Coulomb interaction. W e show that in the weak-lateral confinement regime the natural coordin ates are the relative and the center-of-mass coordinates which are wea kly coupled by the lateral potential. In the strong-lateral confinemen t regime the electrons and holes are weakly correlated and the spectru m can be explained in a single-particle picture.