Fabrication of transparent conductive films with a sandwich structure composed of ITO/Cu/ITO

New transparent conductive films that had a sandwich structure composed of ITO/Cu/ITO multilayer films were prepared by a conventional RF and DC magnetron sputtering process on a polycarbonate substrate without intentional substrate heating. The thickness of each layer in the ITO/Cu/ITO films was kept constant at 50nm/5nm/45nm. The optoelectrical and structural properties of the films were compared with conventional ITO single-layer films and ITO/Cu/ITO multilayered films. Although both films had identical thickness, 100nm, the ITO/Cu/ITO films showed a lower resistivity, 3.5×10−4Ωcm. In optical transmittance measurements, however, the ITO single-layer films showed a higher transmittance of 74% in the wavelength range of 300–800nm. XRD spectra showed that both the ITO and ITO/Cu/ITO films were amorphous. The figure of merit, φTC, reached a maximum of 5.2×10−4Ω−1 for the ITO/Cu/ITO films, which was higher than the φTC of the ITO films (1.6×10−4Ω−1). The φTC results suggested that ITO/Cu/ITO films had better optoelectrical properties than conventional ITO single-layer films.