Raman spectroscopy studies of dopant activation and free electron density of In0.53Ga0.47As via sulfur monolayer doping

We present a Raman spectroscopy study of electron–phonon coupling in In0.53Ga0.47As epilayers doped via the sulfur-monolayer doping method. A high-frequency coupled mode (HFCM) detected above 400 cm−1 shifts with increasing charge carrier density and allows for extraction of the activated dopant concentrations.