Optical properties of GaAs based layers characterised by Raman spectroscopy and photoluminescence

GaAs structures were studied by micro-Raman spectroscopy on chemically bevelled samples. We determined the thickness of the layers, quality of the interfaces the presence of impurities (mainly carbon) in the layers, which cause compensation of free carriers. The results were compared with Hall, photoluminescence and SIMS measurements. From the room temperature photoluminescence measurements we were able to identify the peak position and the band gap of the layers. The low temperature PL shows the incorporated impurities. Our results shows a high level of C and O impurities incorporated to the lattice, which we need to avoid for the development of optoelectronic devices.