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

The role of solution composition in chemical bath deposition of epitaxial thin films of PbS on GaAs(100)

“…In order to eliminate this factor, freshly prepared solutions were used. The CBD set-up and substrate preparation are described elsewhere [2][3][4][5][6][7]. The morphology of the films was studied by X-ray diffraction (XRD), ultrahigh resolution scanning electron microscopy (UHR-SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM).…”

“…Previous studies showed that the microstructure and morphology evolution of thin lead chalcogenide films on GaAs can be controlled by factors such as deposition time, deposition temperature and intermediate lead chalcogenide layers [2][3][4][5][6][7]. Furthermore, it was shown that the evolution of the film morphology is strongly affected by the active deposition mechanism during the course of deposition.…”

“…By controlling the deposition conditions such as time or temperature it is possible to control the active deposition mechanism and consequently the final film thickness and morphology [2][3][4][5][6][7][8]. Inversion of the active deposition mechanism results in a transition from nanocrystalline to monocrystalline thin film morphologies [4][5][6]. Moreover, it was previously suggested that the cation-to-anion ratio, and not simply the cation concentration which is more traditionally considered, is important in defining the nucleation process [9].…”

“…It has been assumed, by considering reactions (4) and (5), that the deposition rate at a constant temperature should be affected mainly by CS(NH 2 ) 2 and NaOH concentrations [10]. Thus, it is reasonable to assume that NaOH and CS(NH 2 ) 2 concentrations are key parameters which can affect the film morphology through change in active deposition mechanism and corresponding growth rate [6]. The effect of reagent concentration is often very complex.…”

Control of morphology and optical properties of PbS nanostructured thin films by deposition parameters: study of mechanism

“…This decrease may change the deposition mechanism from cluster to ion-by -ion [29]. Since the surface characteristics of thin films significantly affect film properties, it is important to anticipate which mechanism will form the surface of the film at different temperatures.…”