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ZnO-polyaniline (PAni) nanocomposites were fabricated through a chemical method using Zinc acetate hexahydrate, ammonium hydroxide and different ratios (5, 15, 20 wt %) polyaniline. The FESEM images of the nanocomposites revealed that ZnO-PAni nanocomposites have a twin-prism structure. The XRD analysis has shown the hexagonal wurtzite structure of ZnO. Presence of P Ani did not cause any change in crystal structure of ZnO. Results of UV-Vis spectra indicate that the ZnO-PAni nanocomposites absorbed visible and ultraviolet light. This may be may be one of the interesting qualities of the prepared ZnO-PAni nanocomposites. Remarkable changes in the properties of the composites were observed, which are due to the interfacial interactions between ZnO and PAni, The interactions caused by hydrogen linkages and surface effects were observed by Raman spectrum analyses. [ABSTRACT FROM AUTHOR]

Copper oxides are deposited by radio frequency sputtering using copper target in the mixture of argon and oxygen gasses. The structural and optical properties of the copper oxides deposited at different sputtering powers have been investigated. All the films are single phase polycrystalline. At low RF power (100 W), the film is monoclinic structure of cupric oxide (CuO). Meanwhile, the films are cubic structure of cuprous oxide (Cu2O) at higher RF power. Field emission scanning electron microscopy images show the films have different morphologies with small grain size and consist of a lot of voids. The analysis of energy dispersive X-ray spectroscopy shows that the ratio of Cu to O is increased as the RF power increased. From the ultraviolet-visible spectroscopy, the films have a broad absorption edge in the range of 300-500 nm. The band gap of the films grown at RF power of 100 W, and 120 W and above, were 1.18 eV and 2.16 eV, respectively. [ABSTRACT FROM AUTHOR]

In this work, the effects of surface orientation of the silicon (Si) substrates on the structural and morphological properties of zinc oxide (ZnO) thin films grown by radio frequency sputtering system were investigated. Silicon substrates with different surface orientations, i.e., Si(100), Si(111), and Si(110) were used. The structural properties of the ZnO thin films were investigated by X-ray diffraction (XRD) technique. The morphological properties of the deposited films were examined by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The XRD results reveal that all the deposited ZnO thin films exhibit a single phase wurtzite ZnO structure with preferred orientation along (002) direction. The FESEM images indicate a change from leave-like to granular-like structure for Si(100), (110) and (111) substrates, respectively. The AFM root mean square surface roughness for ZnO thin films on Si(100), (110) and (111) reveals a decreasing trend. From the results, it was suggested that the ZnO thin films grown on the Si(111) substrate has the best structural and morphological properties. [ABSTRACT FROM AUTHOR]

Infrared (IR) optical properties of a wurtzite ZnO/GaN heterostructure on a wurtzite 6H-SiC substrate are characterized by a polarized IR reflectance spectroscopy. The relation between the reststrahlen features and the optical phonon modes of each individual layer are investigated. It is shown that the transverse magnetic polarized IR reflectance spectrum provides the least loss of information about the optical phonon frequencies of wurtzite crystal. By means of the standard multilayer optics technique and based on an anisotropic dielectric function model, polarized IR reflectance spectra of the studied structure are simulated. Numerical fitting procedure is applied to obtain the best fit of experimental and theoretical spectra. Finally, the optical phonon frequencies and the layers thicknesses of the studied structures are determined. [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO) nanocrystalline were synthesized via oxidizing Zn powder in non-aqueous solvent with addition of Diethanolamine (DEA) as a stabilizing agent. The influence of DEA on the structural, optical properties and the formation of ZnO nanocrystalline were studied. The synthesized ZnO were polycrystalline in structures where sample without the addition of DEA shows high intensity peak of (002) phase compared with sample in the presence of DEA which preferred to grow in (101) direction. SEM micrograph displays the morphology of ZnO nanocrystalline for both of the samples which shows micron size and non-uniform particles for sample without DEA whereas for sample with DEA exhibit smaller size (∼110 nm) and nearly spherical in shape despite of some agglomeration occurs at the interparticle separation. The photoluminescence (PL) spectra shows UV emission peak for both of the samples where sample with the absence of DEA possess lower intensity of UV emission peak compared to samples with DEA which demonstrate stronger intensity despite of having very weak visible secondary emission peak at 530 nm. [ABSTRACT FROM AUTHOR]

In this work, a study on the effect of sonication treatment to the optical and microstructure of ZnO synthesized via precipitation technique has been carried out. ZnO rod- like structure with diameter of 235 nm and 800 nm in length was observed for sample undergoes sonication treatment. Whilst hard agglomerates (where particles are held together by stronger bridges) and bigger size particles was observed without the post-treatment. Both samples demonstrate polycrystalline structure along with sharp X-ray diffraction peak as an indication that the as-prepared ZnO were well crystallized. No other characteristic peaks were observed for other impurities provide that the samples are in pure phase. As for optical behavior, both of the sample exhibit UV emission peaks in photoluminescence (PL) spectrum. However, there is a secondary emission peak centered at 521 nm for sample that undergoes sonication post- treatment process. In summary, the sonication treatment has demonstrated some effect to the structural and optical properties of ZnO. [ABSTRACT FROM AUTHOR]

This article presents photoluminescence (PL) characterization of ZnO thin films deposited by radio-frequency magnetron sputtering method on sapphire and n-type Si (100) substrates. PL measurements were carried out at room temperature to investigate the energy band gaps and optical quality of the ZnO thin films. In order to draw a specific picture of surface morphology of ZnO thin films, atomic force microscope images were taken. All the results were compared to the results obtained from the bulk ZnO sample. The results revealed that the energy band gap of ZnO thin films grown on n-type Si (100) is higher than ZnO on sapphire. However, energy band gap of bulk ZnO is higher compared to both ZnO on n-type Si (100) and sapphire (Al2O3). This is probably due to the crystalline quality because good crystallinity increases the radiation recombination and hence increase the intensity of the NBE emission. [ABSTRACT FROM AUTHOR]

In this work, the structural properties of the zinc oxide (ZnO) thin film on silicon carbide (6H-SiC) grown by radio frequency sputtering technique are investigated thoroughly by means of X-ray diffraction (XRD) technique. Both conventional XRD phase analysis and rocking curve measurements are carried out in order to determine the crystalline structure and the crystalline quality of the ZnO sample. From the phase analysis, intense peaks correspond to ZnO(002), iC(006) and their multiple reflections, i.e. ZnO(004) and SiC(0012) are observed. This result suggests that the ZnO thin film is in wurzite structure. Through the simulation of XRD rocking curve of the ZnO(002) peak, the lattice mismatch of 5.49% is obtained. [ABSTRACT FROM AUTHOR]