Smooth, pseudosmooth, and rough GaAs/Al<i>x</i>Ga1−<i>x</i>As interfaces: Effect of substrate misorientation

Abstract

GaAs/AlxGa1−xAs quantum well and superlattice structures have been grown at 600 °C by molecular beam epitaxy on GaAs (001) substrates exactly oriented or slightly misoriented towards (111) Ga and (111) As. It is shown that for the growth conditions used, the step orientation (nature) has a striking influence on the photoluminescence (PL) features of the grown structures: steps along [1̄10] (Ga-type steps) lead to sharp PL lines (pseudosmooth interfaces), while a considerable broadening of the PL (rough interfaces) is obtained when the steps are along [110] (As-type steps).