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 (1), CH2CF3 (2)) as single-source precursors. The structure of 1 was determined by X-ray crystallography and shown to be a monomer. Films were grown from 1 and 2 by low-pressure CVD using both glass slides and silicon wafers as substrates, at substrate temperatures of 300 and 450 degrees C, respectively. In both cases, the deposited films exhibited XRD patterns that could be fully indexed to orthorhombic stibnite, with stoichiometries in the range Sb2S2.78-3.10 by EDXS. In addition, there is evidence for the formation of small amounts of antimony metal in the films derived from 2. The morphologies of the films are strongly substrate dependent: 1 generates random platelets regardless of substrate, whereas 2 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.