Epitaxial growth of Ca(Ge1−xSnx)2 with group IV 2D layers on Si substrate

Two-dimensional (2D) material is drawing considerable attention as a promising thermoelectric material. This study establishes the formation method of renewed Ca-intercalated group IV 2D materials, Ca(Ge1−xSnx)2 crystals including germanene-based 2D layers. The solid phase epitaxy allows us to form epitaxial Ca(Ge1−xSnx)2 on Si. Atomic force microscopy reveals that the Ca(Ge1−xSnx)2 has island structures. X-ray diffraction proved the epitaxial growth of the Ca(Ge1−xSnx)2 island structures and the increase of the c-axis lattice constant with Sn content increase. The formation of this renewed intermetallic compound including group IV 2D layer opens an avenue for high performance thermoelectric generator/Si.