Studies on surface structures and growth of In ultrathin films on Mo(1 1 0) surface

The surface structures and growth mode of In ultrathin films on Mo(1 1 0) surface have been studied by reflection high energy electron diffraction (RHEED). Three kinds of two-dimensional superstructures α, β and γ were observed in nearly monolayer region of In thickness. The α structure exists stably in wide temperature range from RT to 600 °C. This surface structure is expressed as [1 0 1 4] in matrix notation and has an atomic arrangement of bcc(1 1 0) layer of 23/3 times as large as Mo(1 1 0) plane rotated by 54.7° resulting in inducing compression of In atom by 3.0% in [0 0 1]Mo orientation. The β structure expressed as [1 0 −2 7] in matrix notation appears from 600 to 700 °C and has a smaller surface density than that of α structure. The γ structure expressed as [1 −1 1 2] in matrix notation appears as high temperature phase from 700 to 800 °C. SEM observation reveals that room temperature condensation takes place in accordance with Stranski–Krastanov growth mode.