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(NH2)(2) with excess of NaOH in aqueous solution at a range of deposition temperatures 0-50 degrees 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 degrees 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.