Epitaxial Growth of π‑SnS on PbS Substrates

Epitaxial growth of the newly discovered metastable cubic tin sulfide (π-SnS) material was studied theoretically and experimentally. Lead sulfide (PbS) substrates possess a small lattice mismatch with π-SnS and are therefore suitable substrates for epitaxial growth. Very recently, epitaxial growth of π-SnS(111) on PbS(111) and π-SnS(110) on PbS(110) was reported. The interfacial energies of π-SnS(111) on PbS(111), as well as π-SnS(100) on PbS(100), were calculated and found to be smaller than their corresponding pristine surface energies, which give rise to the stable epitaxial growth of π-SnS on PbS. Moreover, we experimentally confirmed the epitaxial growth of π-SnS(100) onto PbS(100) as predicted by the theoretical results. These results establish the pathway of epitaxial growth of π-SnS compact thin films in desired orientations and thus bring their applications closer.