We present a cross-sectional scanning tunneling microscopy (XSTM) study of the spontaneous ordering of Ga0.48In0.52P
grown on (001) GaAs substrates by molecular beam epitaxy (MBE) and organometallic vapor phase epitaxy (OMVPE), respectively. The (111)-type alloy ordering could be seen clearly in the OMVPE-grown alloy region. On the other hand, the MBE-grown region shows a very small degree of ordering as revealed by the STM. Most of the ordered region shows (InP)1(GaP)1
-type ordering: alternating InP- and GaP-like (11)
planes. In addition to this type of ordering, we also observe another type of ordering consisting of two InP-like (11)
planes and one GaP-like (11)
plane that we call (InP)2(GaP)1
-type ordering. © 1998 American Institute of Physics.