Strained quantum wells in scrolled structures studied by μ-photoluminescence

We investigate the impact of the specific strain gradient on the optical properties of quantum well (QW) structures. This strain gradient emerges if the layer stack is released from the underlying substrate forming a scroll. As the strain state in this configuration changes from compressive to tensile strain the character of the fundamental optical transition in a strained QW is modified. Polarization-dependent low-temperature μ-photoluminescence studies reveal that in all the examined QWs in scrolled structures the valence band has a mixed heavy/light hole like character in agreement with calculations. Therefore, for the interpretation of optical and electronic transport properties of double heterojunctions with a strongly curved geometry the actual built-in strain has to be considered.