Influence of substrate misorientation on vibrational properties of In1−x−yGaxAlyAs grown on InP

Abstract

Using micro-Raman scattering, we have investigated the vibrational properties of nominal In1−x−yGaxAlyAs (x=0.13, y=0.34) layers that were grown lattice matched to InP (100) substrates by molecular-beam epitaxy. In order to control and optimize crystalline quality of these layers, the quaternary alloy films were also grown on (100) substrates oriented 1°, 2°, 3°, and 5° toward the [1̄10] direction. Atomic force microscopy has been employed to investigate the surface topography. The micro-Raman technique has been applied to evaluate the quality of these epitaxial films. Optical phonons show three-mode behavior in these quaternary alloys and the dominant bands observed in the spectra are of three binaries, namely, the GaAs-, InAs-, and AlAs-like optical phonons. The narrowest Raman linewidth and much weaker forbidden modes observed in the layer grown on InP(100) oriented 2° toward the [1̄10] direction, suggest the best crystalline quality among the quaternary alloys grown on misoriented substrates.