Metamorphic InAs/InGaAs quantum dot heterostructures for single-photon generation in the C-band spectral range

Heterostructures with InAs/InGaAs quantum dots and In$_x$Ga$_{1-x}$As(001) metamorphic buffer layers are grown by molecular-beam epitaxy. The structures are designed to obtain single-photon emission in the telecommunication C-band wavelength range. The possibility of reducing the thickness of the In$_x$Ga$_{1-x}$As graded layer in order to form efficient microcavity structures with a cavity length as small as two wavelengths is examined. The structures with metamorphic buffer layers grown on top of an Al$_{0.9}$Ga$_{0.1}$As/GaAs distributed Bragg reflector are grown and characterized by cross-sectional transmission electron microscopy and photoluminescence spectroscopy.