A comparative study of the structure and optical properties of copper sulfide thin films chemically deposited on various substrates

Abstract

Copper sulfide (Cu x S) thin films were chemically deposited from solution onto glass, Si(100) and GaAs(100) substrates. The microstructure and morphology evolution were investigated using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. As-deposited films were found to be amorphous or semi-crystalline, while X-ray diffraction and selected area electron diffraction measurements indicated that the annealed films were composed of a mixture of Covellite (CuS) and Digenite (Cu 1.8 S) phases. The CuS/Cu 1.8 S ratio in the films was influenced by the substrate. Under the same deposition conditions, Cu 1.8 S-rich films were obtained on GaAs and glass substrates, and CuS-rich films were observed on a Si substrate. The deposition rate was also found to be significantly affected by the substrate, with sufficiently higher rates obtained on GaAs. The optical properties of the films were studied using Raman scattering, ellipsometry measurements and UV-VIS-NIR spectroscopy. Irradiation induced phase transformation from amorphous to crystalline phase was observed during Raman measurements due to the local laser irradiation. Band gap energies were found to be relatively similar on all substrates, with strong absorption in the visible range. These results suggest that Cu x S films can be integrated within both Si and GaAs based electronic and electro-optic devices.

Synthesis of CuS nanoparticles by a wet chemical route and their photocatalytic activity

“…The sharp band at 468 cm -1 is attributed to S-S stretching vibration, while a weak band at 263 cm -1 corresponds to A 1g TO mode. Both of these peaks have been associated with the covellite phase of CuS (Munce et al 2007;Safrani et al 2013).…”

The Stability and Structural, Electronic and Topological Properties of Covellite (001) Surfaces.

“…In the 1950s, the discovery of the photovoltaic effect in CdS−CuS heterojunction brought a great attention to CuS, but its structural instability reduced the expectations for this mineral . With the advent of the nanoscience and improvements in the shape and size controlling of micro/nanostructures synthesis enhancing their physical‐chemical properties called again the attention of the researchers .…”

Effect of double substitutions of Cd and Cu on optical band gap and electrical properties of non-colloidal PbS thin films

“…The intensity change in (200) peak, as shown in the inserted pattern, highlights the strong dependency of crystallization on the content of Cu. It has been reported that Cu in the chemical bath deposition may have different reaction kinetics in forming the chalcogenide phase so that the involvement of Cu precursor acts negatively in the sulfide formation[23][24][25].…”