NANOSTRUCTURE OF ORDERING VARIANTS IN (ALXGA1-X)(0.52)IN0.48P GROWN ON DIFFERENT VICINAL GAAS SUBSTRATES

We have investigated the nanostructure of ordered (Al0.5Ga0.5)(0.52)In 0.48P using conventional and high-resolution transmission electron mic roscopy. As in the case of ternary Ga0.52In0.48P, the morphology of th e ordered material depends strongly on the substrate orientation. For a substrate orientation with equal densities of [(1) over bar 10] and [1 (1) over bar 0] steps (and, hence, no preference for one particular ordering variant) a nanostructure is found which exhibits similaritie s to those observed in ternary Ga0.52In0.48P with equivalent substrate orientations. For a substrate orientation which preferentially select s one ordering variant without completely suppressing the formation of the other, we have identified a new type of nanostructure. In this st ructure, antiphase boundaries between domains containing the preferred variant are frequently formed by thin slices of the suppressed varian t. This structural form is directly deduced from high-resolution image s. (C) 1998 American Institute of Physics.