Microstructure of a CuPt-Ordered GaInP Alloy Revealed by Cross-Sectional Scanning Tunneling Microscopy

摘要

The microstructure of a CuPt-ordered GaInP alloy that includes antiphase boundaries (APBs) was studied by cross-sectional scanning tunneling microscopy. By selectively determining the arrangements of In and Ga atoms on a cleaved (110) surface, it was found that (1) the alloy is comprised of small domains (about 5-10 nm in size) of monolayer superlattices of GaP/InP along [111], and (2) the ordered domains are bounded by APBs, presumably lying on (111), (110), (001), or (111), at which the sequence of GaP and InP layers along [111] is 180° out of phase. It was also found that (3) the atomic layers of InP, sandwiched between the ordered domains, are formed on parts of the APBs. It was suggested that the InP layers act as quantum wells and that they emit linearly polarized light parallel to the layers.