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Item type:Publication, Impact of Al-doping on structural, electrical, and optical properties of sol-gel dip coated ZnO:Al thin films(2021-07-01); Thowladda, WarawootAluminum-doped ZnO (AZO) thin films were coated on glass substrates using the sol-gel dip-coating technique. We investigated the effect of Al-doping level on the surface morphology, crystal structure, atomic bonding, and optical and electrical properties of the AZO films. The Al-doping levels in the sol-gel solution were 0, 0.25, 0.50, 1.0, 1.5, and 3.0% with a Zn precursor concentration of 0.50 M. The results show that the grain boundary increased with the doping level, while the crystallite size decreased from 27.2 to 14.2 nm. The AZO films were subjected to tensile stress. The Al-doping levels ≤ of 1.5% encouraged the intensity of the (002) x-ray diffraction peak. The center of the (002) peak shifted from 34.46° to 34.51°, and that of the E2highRaman mode shifted from 435.0 to 432.4 cm-1. Doping with 1.5% Al resulted in a maximum electron concentration of 4.7 × 1018 cm-3 with a minimum resistivity of 2.6 × 10-1 Ω cm and a mobility of 5.14 cm2/V.s. The Urbach energy increased from 88 to 120 meV with increasing doping level. For the AZO films doped with Al (≤1.5%), the analysis of the UV-vis spectra reveals that the position of the conduction band (CB) minimum of the films shifted from -0.16 to -0.21 eV and shifted outward from the valence band (VB). Further Al doping to 3.0% resulted in a VB shift toward CB. The optical band gap reached a maximum of 3.33 eV at 1.5% Al. The combination of tensile stress and electron density due to Al doping influences the shift in the optical band gap of the AZO films. The crystal structure, atomic bonding, and electronic band structure of ZnO films can be modified by Al doping.1 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Al-doped ZnO nanoparticles synthesized by sonochemical-assisted method(2013-10-08); Al-doped ZnO nanoparticles were synthesized by sonochemical method from zinc acetate dehydrate and aluminum acetate as starting precursors. The deionized (DI) water was selected as the solvent. Sonication of the precursor was performed by a Sonics Model VCX 750 for 30 minutes until precipitated product was finally obtained. The as-precipitated powders were calcined at different temperature range of 550-1100 °C for 2 hr. For all samples, their crystal structures were investigated by X-ray diffraction (XRD) and surface morphologies were observed by scanning electron microscope (SEM). The XRD results revealed that, the purity of as-synthesized powders increases when the calcination temperature increases. Moreover, it is noticed that the AlZnO partial peaks will appear when the as-synthesized powders were calcined at 800 - 1000 °C. In addition, SEM micrographs show the increase of agglomeration and the particles when the calcination temperature increases. © (2013) Trans Tech Publications, Switzerland.