Effect of Indium on the Surface Morphology of PbSnTe Films

In this work the effect of indium on the morphology of $\mathrm{Pb}_{1-\mathrm{x}} \mathrm{Sn}_{\mathrm{x}} \mathrm{Te}: \operatorname{In}(x \approx 0.26)$ epitaxial films grown by molecular-beam epitaxy is discussed depending on its concentration and film growth rate. It is shown with atomic force microscopy that under optimal technological conditions (substrate temperature and growth rate) layer-by-layer epitaxy of $\mathrm{Pb}_{1-\mathrm{x}} \mathrm{Sn}_{\mathrm{x}} \mathrm{Te}$ solid solution on BaF
2
(111) substrates is observed. The length of the terraces is up to 250 nm. Moreover, it is shown that the addition of indium in the amount less than one atomic percentage decreases the surface diffusion length of the main components, which is expressed in a decrease in the width of terraces during layer growth. Further increase in indium content (up to 6.3 atomic percentage) completely modifies the growth situation: excess metal precipitation on the surface in the form of inclusions up to several tens of nanometers in height is observed, as well as three-dimensional island growth of the compound itself.