Stark effect in strongly coupled quantum wells

Huge density-dependent blueshift of indirect excitons in biased coupled quantum wells

“…An electric field causes electrons to tend to become confined in one well and holes to tend to become confined in the other well; ''indirect'' excitons are formed from a conduction electron in one well and a heavy hole in the other well, while ''direct'' excitons are formed from an electron and heavy hole in the same well. As reported elsewhere by several authors, indirect excitons in coupled quantum wells have a strong dc Stark shift [12][13][14] and long lifetime. 15,16 In our samples the indirect exciton line shifts about 70 meV ͑40 nm͒ when the dc voltage across the sample is varied from 0 to 5 V ͑i.e., fields up to 60 kV/cm͒, and the indirect excitons have lifetimes of about 100 ns at high applied field.…”

Observation of the exciton Mott transition in the photoluminescence of coupled quantum wells

“…The IX has a large permanent dipole mo-ment determined by the distance between the quantum wells of about 14 nm. The recombination energy of the IX depends linearly on the applied field and can be tuned significantly [22,25,49]. We compare the measured IX and DX peak shifts with our theoretical model and find good agreement, cf.…”

Optical Stark spectroscopy of solids

“…In symmetrical structures, large Stark shifts were found, corresponding to those that would be seen in a well of width equal to the sum of the coupled well widths. An example is provided by the work of Andrews et al [94] who studied a pair of 4.8 nm wells of GaAs separated by a 1.6 nm barrier of Al 0.3 Ga 0.7 As. The exciton structure in the coupled well is more complex, consisting of even and odd parity levels that are coupled by the Stark field.…”