Preparation and Structural Analysis of a PbSe-SnSe Artificial Superlattice

Abstract

A new artificial superlattice composed of PbSe and SnSe, (PbSe)m(SnSe)n, was characterized by the X-ray diffraction method and the cross-sectional transmission electron microscopy. The two materials in their bulk forms possess different crystal structures; PbSe has the cubic NaCl-type structure, whereas SnSe has the orthorhombic SnS-type structure (Fig. 1). It was found from the evaluation of X-ray intensity of the satellite peaks that the samples have an ideal superstructure whose compositional modulation can be described by the step model (Figs. 3,4). In addition, the samples adopt one of four types of lattice structures depending on m and n (Fig. 8). In particular, when they are designed as n>(2/3)m and m≤6, a single crystal artificial superlattice with SnS-type structure can be obtained, while for n