Effective mass dependence of resonant quasi-level lifetime in GaAs–Al xGa 1− xAs double-barrier structures

Abstract

The present work computes the lifetime of the lowest resonant quasi-level in a GaAs–Al x Ga 1− x As double-barrier structure based on the effective mass theory and takes into account the effective mass mismatch nature of well and barrier layers. The calculations showed a strong dependence of the lowest energy and its associated lifetime on both the effective masses of the well and barrier materials and aluminum concentration in the barrier Al x Ga 1− x As material, which is associated to the barrier height. A comparison between a model based on different masses of well and barrier layers and another which considers same effective mass for both layers is made which showed a discrepancy of about 13% related to the lowest resonant energy and of about 29% associated to the resonant quasi-level lifetime both at barrier to well dimensions ratio of 6 and an aluminum composition of 0.45. The present work raises a question about the correct effective masses of tunneling carriers in resonant tunneling devices.