Direct generation of linearly polarized photon emission with designated orientations from site-controlled InGaN quantum dots

Semiconductor quantum dots (QDs) have been demonstrated viable for efficient light emission applications, in particular for the emission of single photons on demand. However, the preparation of QDs emitting photons with predefined and deterministic polarization vectors has proven arduous. Access to linearly polarized photons is essential for various applications. In this report, a novel concept to directly generate linearly-polarized photons is presented. This concept is based on InGaN QDs grown on top of elongated GaN hexagonal pyramids, by which the predefined elongation determines the polarization vectors of the emitted photons from the QDs. This growth scheme should allow fabrication of ultracompact arrays of photon emitters, with a controlled polarization direction for each individual emitter. Researchers in Sweden have unveiled a scheme for fabricating quantum dots that emit linearly polarized light. Anders Lundskog and co-workers from Linköping University controlled the emission from InGaN quantum dots by growing them on top of miniature hexagonal GaN pyramids with elongated bases. They found that the polarization of the emitted light was aligned with the axis of elongation. In principle, the wavelength of the light emitted by the quantum dots can be tuned from ultraviolet to the infrared by adjusting the amount of indium in the InGaN. Benefits of the approach include its compatibility with high-temperature operation and large-area wafer-processing techniques. In the future, this technique could allow the realization of quantum dot-based single-photon emitters with controllable polarization on a single chip.