ZnO nanorods were synthesized at low temperature by hydrothermally heating 0⋅1 M solution of ZnCl 2 for 5, 10 and 15 h at a pH of 10. No template, seeded substrate, catalyst and autoclave were employed for the synthesis of ZnO nanorods. The effect of heating durations on the morphology and crystal orientation of the structure were investigated by using scanning electron microscopy and X-ray diffraction, respectively. SEM images showed that the flower-like structures were formed in 5 h hydrothermally-heated sample, whereas the hexagonal zinc oxide nanorods were perfectly fabricated with the increase in growth time. XRD patterns showed that the preferred orientation in nanorods could be controlled by hydrothermal treatment time. The crystallite size and microstrain were analysed by Williamson-Hall and Halder-Wagner methods. These results revealed the presence of defects in ZnO nanorods. However, by increasing the hydrothermal treatment time, both defects in lattice and crystallite size are decreased.

The structural and optical characteristics of polyvinyl alcohol (PVA) doped with di®erent concentration of Nd 2 O 3 nanoparticles to use an active media for polymer laser were studied. The PVA polymer was considered as the host and Nd 2 O 3 nanoparticles as the active element. The media as a thin¯lm was prepared using spin coating technique. Structural properties of layers were investigated by X-ray di®raction (XRD) pattern and atomic force microscope (AFM) technique. The e®ect of the concentrations of the neodymium source on the optical properties of Nd 2 O 3 /PVA thin¯lms was investigated through UV-Vis absorption spectroscopy and their optical band gap was evaluated. Also, the FTIR and°uorescence spectra of the samples were detected. The°uorescence spectra of¯lms showed that the maximum wavelength occurred at 568 nm with no signi¯cant shift.

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A simple spray pyrolysis technique has been used to fabricate ZnO/Mn thin films with different Mn concentrations (0, 5, 10 and 15 mol.%) for gas sensing applications. X-ray diffraction (with Cu-Ka radiation) patterns of the samples revealed the formation of single-phase wurtzite structure. The samples were characterized using field-emission scanning electron microscopy and scanning tunneling microscopy. The investigation revealed that the surface of pure ZnO thin film appears rougher and containing bigger grains. The response of the pure and Mn-doped ZnO thin-film gas sensors was checked at different temperatures ranging from 120 up to 200°C, to investigate the optimum sensing efficiency. The gas sensing results have demonstrated that the pure ZnO thin film exhibited higher sensitivity to CO 2 gas at 150°C operating temperature, while the sensitivity reduced with the increase in gas pressure. Although the sensitivity of doped samples was lower than the pure sample, the sensitivity increased with the increase in pressure.

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 [Formula: see text] 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.

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The mechanical properties of ceramic–metal nanocomposites are greatly affected by the equivalent properties of the interface of materials. In this study, the effect of vacancy in SiC on the interdiffusion of SiC/Al interfaces is investigated using the molecular dynamics method. The SiC reinforcements exist in the whisker and particulate forms. To this end, cubic and hexagonal SiC lattice polytypes with the Si- and C-terminated interfaces with Al are considered as two samples of metal matrix nanocomposites. The average main and cross-interdiffusion coefficients are determined using a single diffusion couple for each system. The interdiffusion coefficients of the defective SiC/Al are compared with the defect-free SiC/Al system. The effects of temperature, annealing time, and vacancy on the self- and interdiffusion coefficients are investigated. It is found that the interdiffusion of Al in SiC increases with the increase in temperature, annealing time, and vacancy.

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