Diffused GaAs/AlGaAs quantum wells with equidistant electronic states

An alternative way to obtain quantum wells (QWs) with equidistant energy levels is proposed. It consists of interface grading of an initially rectangular QW induced by material interdiffusion. The latter can be realised for example by post-annealing. The electronic states in a large number of interdiffused GaAs/AlGaAs QWs are studied by varying the well width and diffusion length. The calculations are made by means of the envelope function approximation. It is shown that a nearly equidistant energy spectrum can be obtained in diffused QWs (DQWs) by choosing an appropriate value of the initial QW width and by adjusting the diffusion length. The annealing times and temperatures of the sample resulting in the needed diffusion lengths are calculated and reasonable values are obtained. (C) 2002 Elsevier Science B.V. All rights reserved.