Self-Assembled InGaAs/GaAs Quantum Dot Microtube Coherent Light Sources on GaAs and Silicon

We have investigated the fabrication and emission characteristics of InGaAs/GaAs quantum dot microtube-based coherent light sources on GaAs and Si, which are formed by self-rolling of pseudomorphically strained semiconductor bilayers through controlled release from the substrate. Tailoring of the optical modes is achieved by engineering the shape of the microtube ring resonators. Using substrate-to-substrate transfer method, we have also achieved, for the first time, three-dimensionally confined quantum dot microtube optical ring resonators on Si, that are relatively free of dislocations. Sharp polarized and regularly spaced optical modes, with an intrinsic Q-factor of similar to 3,000, were measured at 77 K.