Stark optical transitions in bidimensional arrays of quantum dots

The optical spectrum of a bidimensional array of coupled quantum dots (QDs) under an external electric field is investigated. We show calculations on the interband absorption coefficient in the effective-mass scheme, for several geometrical QD confinement parameters. We study the dependence of the optical properties of the array with the strength and direction of the applied electric field. The different spectra show the characteristic Stark ladder structure associated to each discrete level in the dot depending on the electric field direction. In particular, for a diagonal applied electric field, the energy levels are degenerated, giving an optical spectrum with basically the same features as a linear array. For any other electric field direction, the optical spectrum consists of two overlapped Stark ladders, which are differently spaced.