Growth and characterization of InGaAs quantum dots on metamorphic GaAsP templates by molecular beam epitaxy

The work discussed here focuses on the integration of InGaAs Stranski-Krastanov type quantum dots within a GaAsP metamorphic photovoltaic material matrix via molecular beam epitaxy. Two basic parameters, growth rate and substrate temperature, were studied to determine the nucleation behavior on the GaAsP surface, followed by exploratory growths of encapsulated quantum dot multilayer structures on both tensile (GaAs_yP_1-y/GaAs) and compressive (GaAs_yP_1-y/Si) graded buffers. X-ray diffraction measurements show the presence of satellite peaks due to the superlattice-like periodic structures, indicating sharp, uniform interfaces. Photoluminescence spectra reveal quantum confinement of the InGaAs quantum dots, with 400 meV blue-shifted emission and 52 meV peak width at 20 K.