Variational approach to the calculation of the lowest Wannier exciton state in wide type-II single semiconductor quantum wells

Abstract

The possibility to change the spatial character of the Wannier exciton ground state in a wide single type-II semiconductor quantum well has been studied variationally. A heterostructure with the central layer forming a potential well for holes and a barrier for electrons has been considered. A trial function taking into account the possibility to shift the most probable position of hole from the center of the structure towards interfaces for reducing the distance to electron has been proposed. The exciton transition energy and binding energy were calculated for the structure based on the ZnO one. It has been shown that the proposed trial functions can be used for wide quantum wells for which it describes an exciton state with the carriers localized near the interfaces at a distance of the order of the Bohr radius for bulk exciton.