OBSERVATION OF CUPT-A TYPE ATOMIC ORDERING IN ALXIN1-XAS ALLOYS

CuPt-A type atomic ordering, which has been reported for only Al0.5In0 .5P and Ga0.5In0.5P, was observed in Al-rich AlxIn1-xAs grown on (001) InP substrates by solid-source molecular-beam epitaxy; only the tripl e-period-A type ordering in the [111]A directions has been previously reported for this alloy system grown under a similar growth condition. While the triple-period-A type ordering was observed in Al0.5In0.5As grown with a (2X3) surface reconstruction, the CuPt-A type ordering wa s observed in Al-rich AlxIn1-xAs when the surface showed a (1X2) surfa ce reconstruction during growth. This observation provides strong supp ort for the previous inference that the (1X2) surface reconstruction g ives rise to CuPt-A type ordering. (C) 1998 American Institute of Phys ics. [S0003-6951(98)02044-0].