Magnetic field induced non-linear optical properties in a strained wurtzite GaN/Al_xGa_(1-x)N quantum dot: Effect of internal fields

摘要

Effect of magnetic field on exciton binding energy is investigated in a strained wurtzite GaN/Al_(0.2)Ga_(0.8)N quantum dot in which the strong built-in electric field due to the spontaneous and piezoelectric polarizations is included. Numerical calculations are performed using variational procedure within the single band effective mass approximation by the magnetic field strength. The magnetic field induced interband emission energy of a strained GaN/AlGaN quantum dot is investigated with and without the effect of internal field. The exciton oscillator strength and the exciton lifetime for radiative recombination as a function of dot radius with the effect of magnetic field strength are computed. The total optical absorption coefficients and the changes of refractive index as a function of normalized photon energy in the presence of built-in internal field are analyzed in the presence of magnetic field. The optical absorption coefficients and the refractive index changes strongly depend on the incident optical intensity and the magnetic field. The occurred blue shift of the resonant peak due to the magnetic field will give the information about the variation of two energy levels in the quantum dot. The optical absorption coefficients and the refractive index changes are strongly dependent on the incident optical intensity, the internal field and the magnetic field.