QUANTUM-CONFINED STARK EFFECTS IN SEMICONDUCTOR QUANTUM DOTS

Quantum-confined Stark effects (QCSE) on excitons, i.e., the influence of a uniform electric field on the confined excitons in semiconductor quantum dots (QD's), have been studied by using a numerical matrix-di agonalization scheme. The energy levels and the wave functions of the ground and several excited states of excitons in CdS and CdS1-xSex qua ntum dots as functions of the size of the quantum dot and the applied electric field have been obtained. The electron and hole distributions and wave function overlap inside the QD's have also been calculated f or different QD sizes and electric fields. It is found that the electr on and hole wave function overlap decreases under an electric field, w hich implies an increased exciton recombination lifetime due to QCSE. The energy level redshift and the enhancement of the exciton recombina tion lifetime are due to the polarization of the electron-hole pair un der the applied electric field.