GaAs-based long-wavelength InAs bilayer quantum dots grown by molecular beam epitaxy

Molecular beam epitaxy growth of a bilayer stacked InAs/GaAs quantum dot structure on a pure GaAs matrix has been systemically investigated. The influence of growth temperature and the InAs deposition of both layers on the optical properties and morphologies of the bilayer quantum dot (BQD) structures is discussed. By optimizing the growth parameters, InAs BQD emission at 1.436 μm at room temperature with a narrower FWHM of 27 meV was demonstrated. The density of QDs in the second layer is around 9 × 10⁹ to 1.4 × 10¹⁰ cm⁻². The BQD structure provides a useful way to extend the emission wavelength of GaAs-based material for quantum functional devices.