Tin(II) Aminothiolate and Tin(IV) Aminothiolate Selenide Compounds as Single-Source Precursors for Tin Chalcogenide Materials

Tin aminothiolate compounds Sn-II(dmampS)(2) (1) and Sn-IV(dmampS)(2)Se (2), where dmampS = 1-(dimethylamino)-2-methylpropane-2-thiolate, were synthesized. The molecular structures of 1 and 2 reveal a seesaw and distorted trigonal-bipyramidal geometry, respectively. The H-1 NMR spectrum of 1 shows two types of resonances for the methyl groups of the alpha-carbon, methyl groups of the amino groups, and methylene groups at room temperature. On the other hand, the H-1 NMR spectrum of 2 exhibits a single resonance for each of these groups. According to variable-temperature H-1 NMR analysis, each of these two types of resonances occurring at relatively low temperatures (under 223 K for 1 and under 333 K for 2) are merged as a single resonance with increasing temperature. By using thermogravimetric and thermal decomposition analyses, the residual materials of compounds 1 and 2 are confirmed to be SnS and SnSSe, respectively. Compound 1 was subjected to a metal-organic chemical vapor deposition process, which allowed for the deposition of a dense and well-faceted orthorhombic phase SnS thin film on a SiO2/Si substrate with similar to 200 nm thickness.