Observation of electronic band-structure modification in microtubed quantum well

A semiconductor quantum-well (QW) microtube was fabricated by rolling up an approximately 40-nm thick semiconductor layer containing a narrow-width QW. Subband energy modification in the QW microtube was studied by the change in the photoluminescence properties before and after the layer was rolled up into the microtube. We observed type-II to type-I transition in the electronic subband structure due to the strain effect in the microtube.