Strain states in a quantum well embedded into a rolled-up microtube: X-ray and photoluminescence studies

The shift in the optical response of a quantum well (QW) embedded in the wall of a rolled-up microtube along the tube axis is examined. The microtube is investigated by x-ray microdiffraction to deduce the strain state of the rolled-up heterostructure. Using these results, the optical response of the QW is calculated. A good agreement of the lattice parameters determined by diffraction and photoluminescence is found, if a double shell tube is assumed for certain parts of the tube. Our results indicate that a rolled-up multiwalled microtube experiences different strains on different windings at the same lateral position.