Advances for enhancing the electrical properties and microhardness activity of ZnO/Cu/ZnO thin films prepared by ALD

Substantial consideration is being devoted to the innovation of AC Conductivity, sheet resistance measurements and Microhardness as a function of Cu interlayer thickness of conductive ZnO/Cu/ZnO thin films. ZnO layer was successfully prepared via atomic layer deposition (ALD), while Cu interlayer was deposited by Dc magnetron sputtering. The combination of ZnO/Cu/ZnO with constant ZnO thickness (70 nm) and variable Cu interlayer thickness (20, 50 and 70 nm), has its own individuality in enhancing the performance of the electrical and mechanical properties. The proposed methodology based on the previously published data of the structural characterization, proved to be very effective. The study of (XRD) and (SEM) revealed an increase in particle size with the increase in Cu content. The outcome of the absorption measurements supports the existence of allowed direct transition for ZnO/Cu/ZnO thin films, and the optical energy gap is strongly dependent on the amount of Cu interlayer thickness. The AC conductivity is explored in the frequency range of (1 MHz-1 GHz) and the temperature range of (293 to 423 K). At different frequencies AC conductivity measurements demonstrate a decrement with the increment of Cu content. An agreement between experimental and theoretical results suggests that the behavior of AC conductivity can be successfully explained by Correlated Barrier Hopping (CBH) model, to elucidate the conduction mechanism existing in our ZnO/Cu/ZnO system. A superior combination between mechanical and electrical properties was evaluated by Vickers hardness and the 4-point technique. The obtained results demonstrate that the layer thickness and the layer thickness ratio of ZnO and Cu are the important parameters which are responsible for the improvement of structural, electrical and mechanical properties of ZnO/Cu/ZnO multilayer films. These findings pave the way for the future development of novel energy devices and photocatalytic and absorption applications.