Linear and nonlinear optical absorption coefficients and refractive index changes in strained GaN/AlN quantum dots

The strain distribution and the piezoelectric potential are investigated in GaN/AlN cylinder quantum dot system. The effects of deformation and piezoelectric potential on the conduction band edge are included to investigate the electronic energy levels and the corresponding wave functions in effective-mass approximation. The results indicate that the degenerate energies are separated into two different energies. Based on the energy levels and wave functions, the linear and the third-order nonlinear optical absorption coefficients as well as refractive index changes have been calculated for intraband transition. The total absorption coefficients and refractive index changes will decrease with an increase in the incident optical intensity.