DIRECT IMAGING OF THE EVOLVING AU INSB(III)B INTERFACE/

In situ high-resolution transmission electron microscopy in the profil e geometry has been used to observe the evolving features of the Au/In Sb(111) B-(2 x 2) interface. During Au deposition in the range between 0 monolayer (ML) and similar to 1 ML coverage, the outermost Sb-trime r layer of the InSb(111) B-(2x2) substrate changes in contrast, presum ably revealing that deposited Au atoms are partially captured into it. At similar to 2 ML coverage, an unknown phase emerges on the outermos t layer, beyond which it continues to grow epitaxially in an island st ate, causing partial disruption of the substrate. The phase is identif ied as Au9In4 alloy with a gamma-brass structure determined from a dig ital Fourier transform diffractogram and a transmission electron diffr action pattern. The epitaxial relationship of Au9In4 with the substrat e is given by (111)InSb parallel to(111) Au9In4 and [1(1) over bar 0] InSb parallel to[1(1) over bar 0] Au9In4. The high resolution-profile transmission electron microscopy images of this alloy agree well with the results calculated by the multislice method. (C) 1998 American Vac uum Society.