Study of δ-doped GaAs layers by micro-Raman spectroscopy on bevelled samples

Abstract

Si δ-doped GaAs layers were studied by micro-Raman spectroscopy. The spectra were recorded along the bevelled structure using the light of Ar +-ion laser (514.5 nm line) with high power density. The observed changes in the Raman spectra are discussed in the sense of coupling present between LO phonon and photoexcited electron–hole plasma and plasma of electrons arising from ionised Si atoms. Plasmon-LO-Phonon modes of the coupling of photoexcited plasma in δ-doped GaAs layers were observed for the first time. The minimal thickness of cap layer was estimated in the range of 10–19 nm depending on the doping concentration.