Environmentally Benign Structural, Topographic, and Sensing Properties of Pure and Al-Doped ZnO Thin Films

Abstract

In the present research work, Zn 1– x Al x O thin films with varying proportions of Al ( x = 0.00, 0.01, 0.02, and 0.03) are prepared by a chemical sol–gel spin-coating technique. The crystal structural, morphological, and humidity-sensing properties of the synthesized Zn 1– x Al x O thin films, with varying concentrations of Al ( x = 0.00, 0.01, 0.02, and 0.03), were characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM); a special humidity-controlled chamber was designed for the humidity-sensing studies. In structural and phase analyses, XRD patterns of Zn 1– x Al x O thin films show a hexagonal wurtzite crystal structure. The average crystallite sizes of Zn 1– x Al x O thin films were calculated and found to be ∼18.00, 22.50, 26.30, and 29.70 nm using the X-ray diffraction (XRD) pattern. The surface morphology of Zn 1– x Al x O Al ( x = 0.00, 0.01, 0.02, and 0.03) thin films obtained from AFM micrographs analysis indicates the modification of the spherical grains into nanorods, which were distributed throughout the surface of the films. The SEM image of 3 wt % Al-doped ZnO nanomaterials also shows that spherical nanoparticles changed to nanorod-like structures with a high packing density. Furthermore, increasing the Al-doping concentration from 0 to 3 wt % in ZnO NPs shows lower hysteresis loss, less aging effect, and good sensitivity in the range of 9.8–16.5 MΩ/%RH. The sensitivity of the sensing materials increased with increasing Al-doping concentration, which is very useful for humidity sensors.

High optoelectronic quality of AZO films grown by RF-magnetron sputtering for organic electronics applications

“…The higher grain size is also one of the factors that contribute to higher electrical mobility of the 480 nm film, since it should exhibit less scattering from grain boundaries. The grain sizes are larger than crystallite sizes obtained by XRD (figure 3) because the combination of oriented crystallites forms a grain [36].…”

Mechanistic Insights into the Phase Formation of an Atypical Iron Oxynitride (FexOyNz) System and Its Multifunctional Photocatalytic Applications

“…Further, from the XRD patterns (Figure c), the average crystallite size of the formed particles and microstrain in the system is estimated using Scherrer’s equation D hkl = 0.9λ/β hkl cos θ and ε = β hkl cos θ/4, respectively, where D hkl = average crystallite size in nm, 0.9 = crystallite shape constant, λ = wavelength of X-rays used (0.1513 nm), β hkl = full width at half-maximum (FWHM), θ = Bragg angle, and ε = microstrain. , From the estimations, the crystallite size of FN400 (iron oxynitride) is found to be decreased (19 nm) as compared to those of FO (iron oxide) and FN (iron nitride) particles, which are 23 and 24 nm, respectively. On the other hand, the microstrain in FN400 is found to be more (0.121 ε) compared to FO (0.085 ε) and FN (0.083 ε) systems .…”

Crystallinity Study of Electrodeposited SnO₂ on FTO Substrate

“…Dislocation density. The dislocation density (δ) the line defects present in the which was determined using (Eq.3) [36], given as:…”