Transformations of micron-sized PbTe surface structures induced by low energy ions

Abstract

Formation and transformation of micron-sized structures on PbTe crystal surfaces under impact of low energy Ar+ ions is studied. New phenomena occurring due to interaction of energetic ions and atoms forming the main crystallographic planes of solid crystalline compounds, namely the transformation of ion-induced conical structures into pyramidal ones and the formation of facets of the micropyramids with well-ordered ripples during the process of transformation are revealed. We show that conical-pyramidal transformations occur on any PbTe sputtering surface, but the shape of pyramidal structures depends on the surface crystallographic orientation. If the pyramid originates from the ion-induced conical structure on PbTe target of (100) orientation it has the tetrahedral shape and its facets are covered with pronounced well-ordered ripples arranged in parallel to the base of the pyramid and closed at its edges. We show that: (i) micro-sized conical structures ion-induced on PbTe surface are transformed into pyramidal ones due to the tendency of the PbTe compound to the easy cleavage along crystallographic planes of high reticular density; (ii) the well-ordered ripples on the facets of the tetrahedral pyramids forming from conical structures appear due to self-organization of {111} and {110} crystallographic planes shaping pyramidal facets.