Ideal Crystal Growth from Kink Sites and Fractional-Layer Growth on GaAs Vicinal Substrate by MOCVD

Abstract

ABSTRACT(AIAs)1/2(GaAs)1/2 fractional-layer superlattices (FLSs) are grown on (001) vicinal substrates by metalorganic chemical vapor deposition. Various kinds of GaAs substrates are used. When the substrate is misoriented to [110] direction by 1.92° and [110] by 0.10°, uniform superlattice periods in a large surface area are observed with a bright field transmission electron microscope (TEM). The results suggest ideal crystal growth from kink sites during MOCVD growth, and the distances between the kink sites are equal.On a substrate misoriented to [110] by 1.90°, the superlattice periods exhibit an undulation. This shows that kink flow mode growth is not dominant in the [110] direction. On a substrate misoriented to [010[ by 2.0°, no superlattice periods were observed. From the above results, we discuss the growth mechanisms.Polarization dependent photolumlnescence and optical absorption spectra of FLS were also observed. Electron wave interference devices with lateral periodic potential were fabricated.