Dislocation density-dependent quality factors in InGaN quantum dot containing microdisks

Microdisks incorporating InGaN quantum dots were fabricated using SiO2 microspheres as a hard mask in conjunction with a photoelectrochemical etch step from a structure containing a sacrificial InGaN/InGaN superlattice. Formation of microdisks from two near-identical structures with differing dislocation densities was carried out and investigated using microphotoluminescence. This confirmed the existence of quantum dots through the presence of resolution limited spectral lines and showed a clear correlation between the resulting modes quality factors and the dislocation densities within the disks. The disks with higher dislocation densities showed up to 80% lower quality factors than the low dislocation density disks. © 2011 American Institute of Physics. doi:10.1063/1.3567545 There has been much recent progress in the demonstration of cavity quantum electrodynamics CQED in the solid state using modal engineering of high quality optical cavities to dramatically alter the optical behavior of emitters embedded within. Weak coupling of emitter and cavity can produce controlled single photon emission and ultralow threshold optical sources, 1‐3 while in the limit of strong emitter-cavity coupling unique quantum mechanical states have been observed 4‐7 that could serve as the basis for quantum information processing. 8 Although CQED has been explored in a variety of semiconductor materials, there has been relatively little application to the III-nitrides, although their high-band gaps, large exciton binding energies and possible room temperature RT implementation of CQED effects provide strong motivation to do so. 9