Substrate Effects on Crystal Phase in Atomic Layer Deposition of Tin Monosulfide

Obtaining single-phase tin monosulfide (SnS) films at low temperatures is challenging since cubic (?-SnS) and orthorhombic (?-SnS) polymorphs have similar energies of formation grow under conditions. Here, we show that in atomic layer deposition (ALD) polycrystalline SnS using tin(II) acetylacetonate H2S precursors, the substrate surface greatly influences phase evolution. For example, a silicon (100) substrate, with highly hydroxylated surface, favors growth ?-SnS. Meanwhile, ozone treatment or preannealing same leads to mainly ?-SnS. Just few ALD cycles another oxide sulfide can even more substantially alter outcome. Substrates favor ?-SnS typically produce initially enhanced rates, while those promoting ?-SnS are partially surface-poisoned by precursor ligands. Growth either polymorph self-sustained after its initiation, sustaining factor appears be surface–ligand interaction; preferentially evolves on substrates surfaces rich reactive dangling bonds, chemically inert promote While lattice matching less central, role ligand bonding also helps explain previously reported dependence temperature dose shows promise for area-selective SnS.