Optical Absorption Coefficients in a Polar Quantum Dot Nanostructure

Abstract

The ground state and low lying-excited state energies of a hydrogenic impurity located at the centre of a strained Zn 1−x Cd x Se/ZnSe quantum dot have been computed as a function of dot radius with various Cd content. Calculations have been performed using Bessel function as an orthonormal basis for different confinement potentials of barrier height considering the internal electric field induced by the spontaneous and piezoelectric polarizations. Photoionization cross section of hydrogenic impurity in a quantum dot is investigated. We study the oscillator strengths, the linear and third-order nonlinear optical absorption coefficients as a function of incident photon energy for 1s-1p and 1p-1d transitions. It is found that the optical properties in the strained ZnCdSe/ZnSe quantum dot are strongly affected by the incident photon energy, the confinement potentials and the dot radii and the optical transition energy which depends on the dot radii and the barrier height and tunes the resonant frequency.