Dimensionality Transformation of Exciton State in Quantum Well With Asymmetrical Barriers

In the conditions of 2D-3D dimensionality transformation of one-particle states, the dependence of exciton binding energy Eex on asymmetrical well width h has been theoretically studied. It is shown that the contribution of one-particle continuous spectrum to exciton becomes considerable when the inverse exciton Bohr radius 1ab turns out to be comparable with the critical for 2D-3D transformation value of in-plane wave vector kc. The lack of coincidence between electron and hole kc values leads to the complicated shape of Eex h dependence which has a minimum at intermediate values of h. The minimum value of Eex appears to be less than 3D exciton binding energy.