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Undoped a-axis oriented single crystalline zinc oxide (ZnO) films were deposited by sol-gel dip-coating method. The films were characterized by X-ray diffraction (XRD) and ultraviolet visible (UV-VIS) absorbance spectra. The films of ZnO were deposited on amorphous microscopic glass substrate at various temperatures. The XRD showed that the ZnO film was crystallized with a hexagonal structure with a strong orientation in the (100) plane, which is exactly along the a-axis and beneficial for the development of optoelectronic devices. The optical band gap energy found for this a-axis oriented ZnO film was 3.30 eV through UV-VIS absorbance spectra. The Fourier Transform Infrared Spectroscopy (FTIR) analysis was carried out by taking the IR absorbance spectra for ZnO film deposited on the silicon substrate at 450°C. It showed that the strong Zn–O stretching bond is present in the deposited film.

The surface O or Zn vacancy of ZnO is extremely important, so in this paper we have studied the structural and electronic properties of the ZnOO-polar surface with O vacancy and Zn-polar surface with Zn vacancy comparatively using the first-principles calculations. For the former case, the topmost oxygen atoms relax outward and the angle between Zn–O–Zn bonds in the topmost double-layer decreases to 105.01° with respect to the unrelaxed surface. However, for the latter case, the topmost zinc atoms relax inward and the angle between O–Zn–O bonds in the topmost double-layer increases to 117.61° with respect to the unrelaxed surface. Both the two reconstructed surfaces become semiconducting property in contrast to the metallic property of the unreconstructed surface. The calculated surface vacancy formation energy indicates that the surface with O vacancy is slightly more easier to be formed compared to the surface with Zn vacancy. By employing the technique of ab initio atomistic thermodynamics, we calculated the surface Gibbs free energy to determine the lowest-energy structure, indicating that the surface with O vacancy is more stable than the surface with Zn vacancy under the oxygen poor condition.

In the present study, we demonstrate the performance of Zinc oxide thin film transistors (ZnO TFTs) array subjected to the strain under high bending test and the reliability of TFTs was confirmed for the bending fatigue test of 2000 cycles. Initially, ZnO TFTs were fabricated on Si substrate and subsequently transferred on flexible PET substrate using transfer printing process. It was observed that when the bending radius reached ≥ 11 mm then cracks start to initiate first at SiO₂ bridges, acting as interconnecting layers among individual TFT. Whatever the strain is applied to the devices, it is almost equivalently adopted by the SiO₂ bridges, as they are relatively weak compared to rest of the part. The initial cracking of destructed SiO₂ bridge leads to the secondary cracks to the ITO electrodes upon further increment of bending radius. Numerical simulation suggested that the strain of SiO₂ layer reached to fracture level of 0.55% which was concentrated at the edge of SiO₂ bridge layer. It also suggests that the round shape of SiO₂ bridge can be more fruitful to compensate the stress concentration and to prevent failure of device.

In this paper, ZnO thin film has been synthesized on fluorine doped tin oxide (FTO) glass substrate by annealing the Zn film in air flow. The SEM image shows that the high density and thread-like ZnO nanowires could grow on the thin film. XRD pattern shows that ZnO was the only compound. The high-resolution transmission electron microscopy (HRTEM) results of individual ZnO nanowires show that the nanowires grown on the ZnO thin film are single-crystalline, and the selected area electron diffraction pattern (SAED) shows that the nanowires grow along the (001) direction.

Pure and silver added zinc oxide nanoparticles (ZnO-NPs and ZnO:Ag-NPs) were synthesized through a modified sol–gel method. The prepared samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. In the XRD patterns, silver diffracted peaks were also observed for the samples synthesized at different calcination temperatures of 500°C, 700°C, 900°C except 1100°C, in addition to ZnO. TEM images indicated that the average size of ZnO:Ag-NPs increases with the amount of Ag concentration. The PL spectra of the samples revealed that the increase of Ag concentration results in the increase of the visible emission intensity, whereas by increasing the calcination temperature the intensity of visible emission of the samples decreases.

In this paper, we have investigated the effect of Mn doping on the electrical properties of ZnO thin films. ZnO thin films with different amounts of Mn concentrations (0, 5, 10 and 15 mol.%) were prepared by spray pyrolysis technique. The crystal structure was examined by X-ray diffraction (XRD) analysis. XRD patterns showed that all the samples were crystallized in wurtzite structure while a decrease in crystallinity and switch in preferential orientations were observed in Mn-doped thin films comparing to undoped ZnO. The element composition of all thin films was detected by energy dispersive X-ray (EDX). The surface morphology of the films was investigated using field emission scanning electron microscope (FESEM) and optical properties were studied using UV-vis spectroscopy. UV-vis study revealed that the band gap blueshifts with the increase in Mn content and $E_g$ increases with the increase in Mn concentration. The resistivity and activation energy were measured at room temperature and ranging from 373 K to 573 K. Comparing to undoped ZnO thin film, the resistivity of Mn-doped ZnO films increased because of different parameters such as increasing barrier height energy and reducing the oxygen deficiency.

In the current work, we have demonstrated the phase of ZnO by reference to block theory, in which the phase may be considered to show a paramagnetic ordering between block spins, which in turn comprise random spins that have a majority of individual spins in a given direction. By making use of the Curie–Weiss law of block spins for zinc oxide, we obtained the susceptibility for the lower approximation of the Brillouin function and calculated the resistivity. The resistivity of ZnO mainly stems from spin glass-like disorders according to our analysis.

Hydrophones with three different resonant cavities (microscope slide, cavity with 9.8 mm diameter and 5.7 mm${}^{-1}$ curve surface, and cavity with 14 mm diameter and 6.5 mm${}^{-1}$ curve surface) and with two different electrode structures (interdigital electrode, without the interdigital electrode but with top–bottom structure) were designed and fabricated. Zinc oxide (ZnO) film was deposited on indium–tin oxide/glass as seed layer and ZnO nanocolumns were grown as the piezoelectric material. Grown ZnO nanocolumns were used in all samples as the sound receiver of all designed hydrophones to enhance the sensing effect and efficiency of fabricated hydrophones. The electrode mask was then adhered on the surfaces of ZnO nanocolumns to complete the electrodes of designed resonant cavity. While measuring the hydrophones without interdigitated electrode, the measurement probes were contacted directly on the substrate and on the top layer of the material. Finally, the resonant cavities in all designed hydrophones were encapsulated using epoxy resin to finish the package of the fabricated hydrophones, and then the sound receiving performance of the hydrophones was evaluated in the water and the results were well compared in this study.

The double-stacked gate dielectrics (DSGD), which consisted of either NbLaO/Al₂O₃ or NbLaO/SiO₂, were used to improve the electrical performance of zinc oxide thin-film transistor (ZnO-TFT) with single-layer NbLaO gate dielectric (SLGD). Compared to ZnO-TFT with SLGD, the ZnO-TFTs with DSGD exhibit better electrical performance, specifically for the device with the NbLaO/SiO₂ DSGD, with an increase of the field-effect mobility from 5.77 cm²V${}^{-1}$s${}^{-1}$ to 39.64 cm²V${}^{-1}$s${}^{-1}$, an enhancement of the on/off current ratio by two orders of magnitude, a reduction of the subthreshold slope from 110 mV/decade to 70 mV/decade. The performance enhancements are attributed to a low root-mean-square surface roughness of less than 0.3 nm and a low trap-state density of less than $6\times 10^{11}$ cm${}^{-2}$ (even $2.4\times 10^{11}$ cm${}^{-2}$ for the NbLaO/SiO₂ DSGD) in the bulk of the channel and at the ZnO/NbLaO interface. The results imply that ZnO-TFTs with DSGD have the potential for the application of high-resolution flat panel display.