Universal Growth Scheme for Quantum Dots with Low Fine-Structure Splitting at Various Emission Wavelengths

It would be terrific to use semiconductor quantum dots to produce entangled photons in a quantum communication network, but entanglement is complicated by the exciton spin splitting of typical dots. The authors present a growth strategy that improves the in-plane aspect ratio of $I\phantom{\rule{0}{0ex}}I\phantom{\rule{0}{0ex}}I-V$ quantum dots by 72%, greatly reducing the fine-structure splitting of exciton eigenstates that is the root of the problem. Their approach can be implemented with either molecular-beam or vapor-phase epitaxy, to yield dots that emit at telecommunication wavelengths and are easily incorporated into optical cavities.