The Roles of the CuO Buffer Layer on the Photocatalytic Activity of the p-Si/p-CuO/n-ZnO Composite Films

The photocatalytic activity of p-Si/p-CuO buffer layer/n-ZnO nanorod (NR) composite films was studied using experimental and simulation methods. The simulation results indicated that in the p-Si/p-CuO/n-ZnO composite film, the 250 nm CuO buffer layer contributes the highest value of 11% to the total current density compared to the p-Si/n-ZnO composite film. Besides that, the experimental results also indicated that by introducing the p-CuO buffer layer, the pseudo-order rate constant (k) could be enhanced up to 12% compared to the composite film without the p-CuO buffer layer - the p-Si/n-ZnO composite film. Furthermore, the recycle result indicated that the pseudo-order rate constant - k value decreased sharply after the first three reaction cycle times and gradually stabilized at a value of 0.88 s−1 after the fourth reaction cycle. Therefore, it can be concluded that by introducing the 250 nm thick of p-CuO buffer layer in the p-Si/p-CuO/n-ZnO NRs composite film, the photocatalytic activity could be improved up to 12% compared to that without the p-CuO buffer layer. In addition, the composite film, p-Si/p-CuO buffer layer/n-Zno, is a reusable photocatalyst with high photostability.