Highly Performing Al:ZnO Thin Films Grown by Pulsed Laser Deposition at Room Temperature

As research in the field of Transparent Conducting Oxides is forced to move away from indium-based materials, the need to obtain highly performing indium-free transparent conducting layers for photovoltaic and optoelectronic applications is continuously growing. Aluminum-doped ZnO is a suitable candidate, and Pulsed Laser Deposition a powerful technique for its synthesis in a controlled way. Al:ZnO films were grown by pulsed laser deposition at room temperature with a fixed oxygen atmosphere (2 Pa O-2). We studied the influence of film thickness (from 100 nm to 1 mu m) on structural and functional properties, which were characterized by X-ray Diffraction, Atomic Force and Scanning Electron Microscopy, Van der Pauw and Hall electrical measurements and transmittance spectra. Low resistivity (of the order of 10(-4) Omega cm) and high transparency (> 80% in the visible range) were found, compatible with the state of the art for films grown on heated substrates. Competitive results were also obtained for AZO films deposited on polymeric substrates, thus opening the possibility to develop flexible electrodes for application in organic-hybrid photovoltaic or optoelectronic devices.