Tuning of intersubband transition in a quantum ring by external electric field

In this paper, energy states of electrons in a semiconductor quantum ring have been calculated in the presence of an electric field perpendicular to the plane of the ring. The external field alters the potential energy profile of the structure and thus controls the electron energy-eigenvalues inside the ring. The energy subbands are computed taking n-type GaAs quantum ring as an example. The effect of electric field is to lower the energy states of the electrons linearly at low fields and non-linearly at high fields. The energy for inter-subband transition between two lowest quantum states in the direction of the field increases with increase in electric field, which shows the possibility of fine wavelength tuning using electric fields.