Optical absorptions of a negatively charged exciton in quantum dots

Abstract

The optical absorptions are investigated for a negatively charged exciton (trion) in a quantum dot. Calculations are performed by using the matrix diagonalization method and compact-density approach within the effective-mass approximation. Based on the computed energies and wave functions, the linear and third-order nonlinear total optical absorption coefficients and refractive index changes have been studied for the heavy-hole and light-hole trions, respectively. The results show that the optical absorption coefficients and the refractive index changes are strongly affected by the confinement frequency and the hole mass. We find that the optical absorptions and refractive index changes of the trion are larger than those of the exciton in the quantum dot with the same conditions.