Raman study of Al0.54In0.46P/GaAs interfaces grown by solid source molecular beam epitaxy

An Al0.54In0.46P/GaAs superlattice was grown using a new approach to molecular beam epitaxy that employs solid-source valved crackers to supply the As4 and P2 group V fluxes. The superlattice sample was characterized by off-resonance Raman backscattering spectroscopy. In comparison to other III-V superlattices, the acoustic region of the Raman spectrum from this superlattice was especially rich, and phonon doublets up to the seventh order were visible in the spectrum. The interface roughness in the superlattice was determined to be two monolayers using a simple photoelastic model to characterize the intensities of the folded longitudinal-acoustic phonon peaks. The minimal intermixing present at the interfaces demonstrates the ability to abruptly switch between group V fluxes using the solid-source valved crackers.