Field localization of electrons in ${\mathrm{In}}_{0.53}$${\mathrm{Ga}}_{0.47}$As/${\mathrm{In}}_{0.82}$${\mathrm{Ga}}_{0.18}$${\mathrm{As}}_{0.40}$${\mathrm{P}}_{0.60}$ quantum wells studied by electroabsorption

The influence of electric fields on the optical absorption of ${\mathrm{In}}_{0.53}$${\mathrm{Ga}}_{0.47}$As quantum wells with ${\mathrm{In}}_{0.82}$${\mathrm{Ga}}_{0.28}$${\mathrm{As}}_{0.40}$${\mathrm{P}}_{0.60}$ barriers has been studied with use of electroabsorption using small modulating fields. Samples with thick barriers respond by the quantum confined Stark effect while those with thin barriers show a more complicated behavior, related to the reduction of interwell coupling by the increasing field. Transitions corresponding to electron transfer over several barriers are observed at low fields, shifting rapidly with field and decreasing in strength. At high fields, the electron states decouple and the spectra correspond to those of uncoupled wells. The different regimes are distinguished by the line shape of their electroabsorption spectra. The results are compared with tunnel resonance calculations based on Airy functions.