Raman and photoluminescence characterisation of InxGa1−xP self-assembled quantum dots on GaP(100) substrate

We present here Raman and photoluminescence (PL) measurements of In.5Ga.5P self-assembled quantum dots (SAQD) on GaP, at each stage of the growth. Observation of confined acoustic phonons ∼32 and 49 cm−1 in In5Ga5P SAQDs is the most important result of these Raman scattering measurements. The PL data at 12 K shows that the highest PL peak observed corresponds to bound exciton in the substrate, buffer layer and wetting layer (WL). We find that PL spectra from 2-D WL shows blue shift due to confinement and increased oscillator strength for the transition. These uncapped SAQDs introduce nonradiative transitions leading to quenching of PL from WL. Raman data at 12 K shows that interface layer at InGaP/GaP interface increases in In content as nominal thickness of InGaP layer increases.