Nanomaterials @ Interfaces Research Group

Spontaneous reaction of Pb(NO₃)₂ and CS(NH₂)₂ in aqueous NaOH solution was used for depositing PbS thin films on GaAs(1 0 0) single-crystal substrates. The effects of reagent concentrations at constant deposition time and temperature were studied. The concentrations of NaOH and CS(NH₂)₂ were found to be major factors which affect the film morphology and microstructure. Single-crystal film growth was induced by increasing pH, which, as in the case of increasing temperature, leads to enhanced availability of sulfide anions in solution. X-ray diffraction and transmission electron microscopy (TEM) indicated development of a 〈1 1 0〉 texture with increasing film thickness. Epitaxy was determined by cross-sectional TEM analyses, which showed a (0 1 1)_PbS||(1 0 0)_GaAs, [0 over(1, -) 1]_PbS | | [0 1 over(1, -)]_GaAs orientation relationship between the film and the substrate.