The formation of CuO nano-wire structures to enhance the optoelectronic properties of Al doped ZnO layers

• CuO nano-wire structures are first observed on the roughed surface of AZO seed layers.
• CuO nano-wires are mainly single crystal phases.
• Improvement of the optoelectronic properties on the AZO thin film by the optimum density of CuO nano-wire structures.
• Promoting the application of AZO thin film on transparent conductive oxide.

In this study, CuO nano-wire structures are first observed on the roughed surface of AZO seed layers. The CuO nano-wire structures have different densities with various Cu deposited time. After the deposition of a AZO capping layer, the structure and optoelectronic properties of the finished AZO/CuO nano-wires/AZO thin film are studied. Structural characterization by high-resolution transmission electron microscopy (HRTEM) indicates that the CuO nano-wires are mainly single crystal phases. The optimum density for the CuO nano-wire structures is achieved by depositing Cu at 50 s. This gives the lowest resistance of 1.4 × 10−4 Ω-cm and the average transmittance from 400 to 800 nm is about 84%. The best figure of merit for the AZO/CuO nano-wires/AZO layer is 1.54 × 10−2 (Ω−1), which shows that the application of AZO on transparent conductive electrode is viable.