Influence of Annealing Temperature on the Structural, Morphological, Optical and Electrical Properties of Cu7S4 Thin Films Prepared by Chemical Bath Deposition

In this work Cu7S4 thin films were synthesized successfully on glass substrates by a simple and cost-effective chemical bath deposition method. These films were annealed at various temperatures of 150 °C, 250 °C, and 350 °C. The influence of the annealing temperature on the structural, morphological, optical, and electrical properties was investigated. XRD analysis revealed that the as-prepared and post-annealed films are anilite Cu7S4, AFM measurements proved the films were free of voids and cracks with homogeneous surfaces, optical measurements revealed a blue shift in the band gap of about 0.54 eV as compared to that of bulk Cu7S4, while electrical measurements indicated the films have high conductivity. The optimum result is achieved in the films annealed at 150 °C where highest crystallinity, low crystallite size, and highest conductivity are recorded. This could be used for many applications such as optoelectronics, solar cell, and gas sensors.