Deposition of Antimony Sulfide Thin Films from Single-Source Antimony Thiolate Precursors

Antimony sulfide thin films have been deposited for the first time by MOCVD using antimony thiolates Sb(SR)₃ (R = Bu^t (<b>1</b>), CH₂CF₃ (<b>2</b>)) as single-source precursors. The structure of <b>1</b> was determined by X-ray crystallography and shown to be a monomer. Films were grown from <b>1</b> and <b>2</b> by low-pressure CVD using both glass slides and silicon wafers as substrates, at substrate temperatures of 300 and 450 °C, respectively. In both cases, the deposited films exhibited XRD patterns that could be fully indexed to orthorhombic stibnite, with stoichiometries in the range Sb₂S_2.78_-_3.10 by EDXS. In addition, there is evidence for the formation of small amounts of antimony metal in the films derived from <b>2</b>. The morphologies of the films are strongly substrate dependent:  <b>1</b> generates random platelets regardless of substrate, whereas <b>2</b> deposits a uniform film with islands of needle morphology on glass or long rods of stacked platelets on Si. A film deposited on glass is photoactive and has a band gap of 1.6 eV.