Metal sulfide semiconductors with technological application in the photovoltaic field were prepared by electrodeposition. In particular, we used the E-ALD (Electrochemical Atomic Layer Deposition) to grow CuS and Cu-Zn sulfides on Ag substrates. With the aim of performing a chemical, morphological and structural characterization of the grown films, a TEM (Transmission Electron Microscope) study, for morphology and composition at the nanometer level, and SXRD (Surface X-Ray Diffraction) investigations, for the structural information, were undertaken. SXRD measurements have been performed at the ID03 beamline of ESRF (Grenoble). In particular, an in-situ experiment of crystal growth was attempted and this allowed to investigate the growth mechanism of CuS thin films. The growth of the film was monitored by following the evolution of the Bragg peak and monitoring the presence of powder diffraction rings. No shifts of the Bragg peaks were observed during the film growth, indicating a homogeneous growth process from the first layers. The intensity of the Bragg peak starts to be appreciable from the 15th deposition cycle, suggesting that the material crystallizes with low symmetry and a large elementary cell. Owing to the fact that the SXRD analysis is performed investigating the reciprocal space of the electrode over which the chalcogenide film is growing, the extraction of the Miller indices of the chalcogenide films is difficult. In order to check the possibility for a model to represent the actual chalcogenide film structure obtained by E-ALD, a procedure to derive the expected Miller indices of many models for the chalcogenide films on a silver single crystal has been implemented. No shifts in the Bragg peak position are observed comparing CuS and Cu-Zn sulfides, suggesting a similar crystalline structure. Analysis of these data are still in progress but all the samples show a high crystallinity, proposing E-ALD as method to grow structurally ordered thin films.
An in situ and ex situ SXRD and TEM microscopy study of CuXSZ and CuXZnYSZ thin films
Di Benedetto F;
2014
Abstract
Metal sulfide semiconductors with technological application in the photovoltaic field were prepared by electrodeposition. In particular, we used the E-ALD (Electrochemical Atomic Layer Deposition) to grow CuS and Cu-Zn sulfides on Ag substrates. With the aim of performing a chemical, morphological and structural characterization of the grown films, a TEM (Transmission Electron Microscope) study, for morphology and composition at the nanometer level, and SXRD (Surface X-Ray Diffraction) investigations, for the structural information, were undertaken. SXRD measurements have been performed at the ID03 beamline of ESRF (Grenoble). In particular, an in-situ experiment of crystal growth was attempted and this allowed to investigate the growth mechanism of CuS thin films. The growth of the film was monitored by following the evolution of the Bragg peak and monitoring the presence of powder diffraction rings. No shifts of the Bragg peaks were observed during the film growth, indicating a homogeneous growth process from the first layers. The intensity of the Bragg peak starts to be appreciable from the 15th deposition cycle, suggesting that the material crystallizes with low symmetry and a large elementary cell. Owing to the fact that the SXRD analysis is performed investigating the reciprocal space of the electrode over which the chalcogenide film is growing, the extraction of the Miller indices of the chalcogenide films is difficult. In order to check the possibility for a model to represent the actual chalcogenide film structure obtained by E-ALD, a procedure to derive the expected Miller indices of many models for the chalcogenide films on a silver single crystal has been implemented. No shifts in the Bragg peak position are observed comparing CuS and Cu-Zn sulfides, suggesting a similar crystalline structure. Analysis of these data are still in progress but all the samples show a high crystallinity, proposing E-ALD as method to grow structurally ordered thin films.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
