Effect of temperature and pH on direct chemical bath deposition of cuprous oxide thin films

Uniform and crystalline cuprous oxide (Cu2O) thin films were deposited on corning glass substrates precoated with a thin layer of CuxS by chemical bath deposition at low temperature (≤ 70 °C). The influence of temperature and pH was investigated on the structural, morphological, optical and electrical properties of the thin films. It was found that the complexing agent triethanolamine plays a key role to get crystalline films. Furthermore, the increase of pH changes preferential orientation from the plane (111) to the plane (200), which favors the formation of compact thin films, resulting in an increase of their conductivity. Finally, the increase of temperature increases the thickness and stimulates the formation of well-defined morphologies, which enhances transmittance and reduces the band gap.