Raman Scattering Studies on the Thin Graded Band Gap AlGaAs Hetero-Epitaxial Layer

Thin graded hetero-epitaxial AlGaAs layer has been grown from the undersaturated Liquid Phase Epitaxial (LPE) technique. The grown layers have been characterized using Laser Raman scattering studies. The peak position and intensity ratio of GaAs and AlAs like LO phonon frequencies have been measured and compared with conventional LPE grown AlGaAs epitaxial layer. The behaviour of GaAs and AlAs like LO phonons has been found to vary with the aluminum composition in the grown layer. Raman peak positions have been observed to shift to lower wavenumber in GaAs like LO phonon and higher wavenumber side of AlAs like LO phonon. Aluminum free features have been noticed in IEE grown AlGaAs (x > 0.8) hetero epitaxial layers.