ELECTRIC-FIELD EFFECTS ON EXCITONS IN QUANTUM DOTS

Using low-temperature microphotoluminescence spectroscopy we have inve stigated the effect of a lateral electric held on quantum dot excitons trapped by monolayer width fluctuations in a narrow quantum well. We observe a redshift of the ground state and several excited states, whe n a lateral field is applied. This Stark shift is reduced when the dot is populated with several excitons that screen the electric field. Th e lines broaden increasingly at high fields, which is attributed to fi eld-induced lateral tunneling out of the dot.