Microstructure and morphology evolution in chemically deposited semiconductor films: 4. From isolated nanoparticles to monocrystalline PbS thin films on GaAs(100) substrates

Thin lead sulfide films were grown on single crystal GaAs(100) substrates by chemical deposition using Pb(NO₃)₂ and CS(NH ₂)₂ with excess of NaOH in aqueous solution at a range of deposition temperatures 0-50°C. The microstructure and morphology evolution were studied as a function of the deposition conditions, resulting in a wide range of microstructures. Ultrahigh resolution scanning electron microscopy and atomic force microscopy indicated a systematic change in particle shape and surface morphology as a function of deposition temperature and deposition time. X-ray diffraction of 200-500 nm thick films indicated a dominant (110) texture throughout the deposition temperature range. At deposition temperatures above 40°C, single crystal films were obtained. Cross-sectional transmission electron microscopy analyses showed a unique (011)pbs||(100)_GaAs and [100]_Pbs||[011]_GaAs orientation relationship.