Exciton states and oscillator strengths in a cylindrical quantum wire with finite potential under transverse electric field

Abstract

The effects of a transverse electric field on the electronic structure, exciton states, and oscillator strengths in a cylindrical quantum wire (QWR) are theoretically investigated. We consider a QWR made of GaAs material surrounded by a barrier of Al0.3Ga0.7As of finite depth potential. The electronic structure of the QWR, at the single electron level of theory, is obtained inside the effective mass approximation using the plane wave method, while the exciton states and transition oscillator strengths are calculated using the variational principle. The results show that the exciton oscillator strength is strongly enhanced due to the excitonic effect. The external electric field lifts the degeneracy of the electron or hole states. The energy levels of the electron and hole, exciton binding energy and exciton oscillator strength decrease with the increasing of the strength of the electric field. The stronger the electric field, the weaker the excitonic effect is. The influence of the electric field on exciton states and oscillator strengths becomes more significant for wide quantum wires. However, in sufficiently narrow wires, the influence of the electric field is also significant at small fields.