Observation of a New CuPt-Type Ordered-Phase with Orientation in the [111]A Direction in Al0.5In0.5P Alloy

Abstract
A new type of CuPt ordered-phase (CuPt-A) with orientation in the [111]A and [1̄1̄1]A directions was found in Al0.5In0.5P grown at 520° C on exact (001)GaAs substrate by gas-source molecular-beam epitaxy. Weak formation of conventional CuPt-B type ordered phase was also observed in the same AlInP layer. The surface reconstruction observed by RHEED during the growth was (2×2). At a growth temperature of 560° C the surface reconstruction was (2×1) and only conventional CuPt-B was formed. A step array parallel to [1̄10] and descending towards [110] was found to promote formation of the CuPt [111]A variant.