Ultrahigh vacuum i n s i t u transmission electron microscopy observations of molecular-beam epitaxially grown InSb(111)

Ultrahigh vacuum in situ transmission electron microscopy has been used to investigate homoepitaxial growth processes and a 2×2 surface reconstruction of InSb(111) by molecular-beam epitaxy. When the incident fluxes (1:1) of Sb4 and In1 are impinged onto the substrate, the respective molecules form homoepitaxially grown InSb films, leaving an excess molecule Sb* which does not contribute to the formation of the InSb films. As a result, there exists a critical temperature (Th) for the condensation of Sb* molecules. Below Th, the surface concentration of Sb* (nSb*) becomes higher than a critical concentration for the condensation (ncSb*), so that two phases (InSb+Sb) grow in a polycrystalline state. However, above Th as nSb* becomes lower than ncSb*, InSb films grow with the 2×2 reconstructed surfaces. This critical temperature is defined as a homoepitaxial temperature. Quantitative interpretations of Th are discussed.