Room-temperature optical orientation of the exciton spin in cubicGaN∕AlNquantum dots

Abstract

The optical orientation of the exciton spin in an ensemble of self-organized cubic $\mathrm{Ga}\mathrm{N}∕\mathrm{Al}\mathrm{N}$ quantum dots is studied by time-resolved photoluminescence. Under a polarized quasiresonant excitation, the luminescence linear polarization exhibits no temporal decay, even at room temperature. This demonstrates the robustness of the exciton spin polarization in these cubic nitride nanostructures, with characteristic decay times longer than $10\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$.