PERIODIC LATERAL STRUCTURE OF AL CONTENT MODULATIONS IN ALGAAS GROWN ON VICINAL (111)A GAAS BY MOLECULAR-BEAM EPITAXY

The photoluminescence spectra of single quantum well (SQW) structures grown on (111)A GaAs misoriented 3-degrees towards the [100] direction are red shifted and broadened. These spectra also have extra peaks on the high-energy side, and the surface of the SQWs show giant steps to wards [110] and [101] direction. Cross-sectional transmission electron microscopy of the SQWs on the 3-degrees-misoriented (111)A surface cl early shows that the Al content is lower in the AlGaAs regions paralle l to the (221)A or (331)A orientation and that the widths of GaAs well s increases at the risers of the giant steps towards [110] and [101]. On the exactly (111)A surfaces, the peak cathodoluminescence wavelengt h shows that the Al content on the AlGaAs triangle facets consisting o f (221)A or (331)A planes is lower than on the flat surfaces. The AlGa As layers grown on (111)A GaAs misoriented toward [011] have photolumi nescence spectra whose intensity is stronger, and whose line width is narrower than the spectra from the AlGaAs layers grown on (111)A GaAs misoriented toward [100]. These phenomena are especially active for th e AlGaAs grown on (111)A GaAs misoriented toward [110]. These novel la teral structures are most likely caused by the different sticking coef ficients of Ga adatoms between on (111)A surfaces and (110) surfaces.