Tin(iv) chalcogenoether complexes as single source precursors for the chemical vapour deposition of SnE and SnE (E = S, Se) thin films.

The molecular Sn(iv) complexes, [SnCl{BuS(CH)SBu}] (2), [SnCl(BuS)] (3) and [SnCl(BuSe)] (4) have been prepared in good yield from reaction of SnCl with the appropriate chalcogenoether ligand in anhydrous hexane and, together with the known [SnCl{BuSe(CH)SeBu}] (1), employed as single source precursors for the low pressure chemical vapour deposition of the corresponding tin dichalcogenide thin films. At elevated temperatures the bidentate ligand precursors, (1) and (2), also form the tin monochalcogenides, SnSe and SnS, respectively. In contrast, (3) gave a mixture of phases, SnS, SnS and SnS and (4) gave SnSe only. The morphologies, elemental compositions and crystal structures of the resulting films have been determined by scanning electron microscopy, energy dispersive X-ray spectroscopy, grazing incidence X-ray diffraction and Raman spectroscopy. Van der Pauw measurements on the SnS, SnS and SnSe films confirm their resistivities to be 2.9(9), 266(3) and 4.4(3) Ω cm, respectively.