X-ray diffraction and transmission electron microscopy analysis of ordering and structure in Al1-xInxAs thin films

This paper presents an x-ray diffraction and transmission electron microsco py analysis of Al1-xInxAs grown by molecular beam epitaxy. Two samples grow n on (001) InP at temperatures of 370 and 400 degrees C are characterized. The first, which contains a high density of twin lamellae, exhibits triple- period short-range ordering with a rather short correlation range normal to the (111) planes. Within these (individual) planes, the concentration, how ever, is uniform over a considerably greater distance, leading to a highly anisotropic scattering. This is the first observation of triple-period shor t-range ordering in a sample that exhibits 2 x 1 surface reconstruction. Th e second sample exhibits CuPt-type short-range ordering with scattering tha t is significantly streaked, suggestive of lamellar-shaped ordered domains. Both samples contain high densities of stacking faults leading to addition al sharp streaking along symmetry-allowed (111) directions.