the effect of Al concentration on the structural optical and electrical properties of AZO nanostructures on flexible polyimide films
Project no. 23618 · Status: Kapanmış · 2022
Summary
<p>It was investigated with this project how the morphological, optical and electrical properties of PI/AZO nanostructures obtained by electrochemical deposition method on surface modified polyimide film change depending on aluminium concentration. SEM analysis results to examine the surface properties of the samples showed that AZO nanostructures changed from hexagonal pellet structure to hexagonal nanorod structure with increasing Al concentration. X-ray diffraction (XRD) method was used to analyses the crystal structure of undoped ZnO and AZO films. XRD analyses showed that AZO films have polycrystalline structure, hexagonal phase, and preferential orientation (002) and that the increase in the concentration of aluminium does not affect the orientation of the films. XPS analysis was also performed to investigate the chemical states of undoped and Al-doped ZnO. As a result, the chemical bonds obtained by XPS analyses of our samples were compatible with our XRD analyses and supported the phases and formations observed in the structure. Transmittance analyses of the samples were made in the wavelength range of 200-900 nm. When the transmittance analysis results are examined, it is seen that all prepared ZnO:Al thin films exhibit high optical transmittance (T>75%) in the visible region. In addition, it was observed that the optical band gap increased in accordance with the increase in Al doping concentrations. The electrical properties of the samples were investigated at room temperature and under vacuum in the range of 77 K-470 K. As a result of the electrical analysis, it was found that AZO films showed high electrical conductivity and improved electrical properties compared to undoped ZnO films. It has been observed that the electrical properties of AZO films are further improved with increasing temperature in the vacuum environment. Among the samples, the AZO film prepared at 7.5 mM Al concentration, which has the lowest resistivity (2.31 x 10-3 ohm.cm) and sheet resistivity (30.80 ohm/sq) values at room temperature, decreased to 5 x 10-4 ohm.cm and 6.61 ohm/sq values, respectively, with increasing temperature. The I-V graph of this sample also taken under 370 nm UV light showed that the sample responds to this wavelength. These results showed that temperature and UV light had a significant effect on AZO films. Thus, high quality and efficient material production was realized for extensive advanced technology application projects to be carried out in the future.</p>