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Characterization of ZnO nanowire arrays.
When a large number of ammonium groups connected with long-chain molecules in polyethyleneimine are selectively adsorbed on the non-polar surface of ZnO crystals, the surface free energy and growth of these crystal surfaces can be changed, and finally increase the aspect ratio of the nanowires; the presence of ammonia can effectively prevent the homogeneous nucleation of ZnO in the solution.
It can be seen that all films are hexagonal wurtzite ZnO structure (JCPDS card No. 36-1451).
A large number of ammonium groups connect to long-chain molecules in PEI can be selectively adsorbed on the non-polar faces of ZnO crystals, which changes the surface free energy and growth rate of these crystal faces, thereby inhibiting the growth of these crystal faces, but its axial growth is not affected.
This is because the density of the nanowires is mainly determined by the number of ZnO nuclei, which contains a main crystal axis along the [001] direction.

The charged defects in lattice structure grow in number when Al element mixed in ZnO, and free electron is easier to form, the conductivity of the AZO materials increased strongly.
Results and discussion 2.1 X-ray diffraction Fig. 1 displays the XRD patterns of the pure ZnO and Al doped ZnO samples .
All peaks of the sample can be indexed to hexagonal wurtzite ZnO (JCPDS card no. 36-1451).
The gas sensing mechanism can be described in terms of an adsorption/desorption process of oxygen atthe surface of sensing materials.There are a number of donor defects in the ZnO crystal structure, and Al3+ ion radius is larger than the Zn2 +, therefore it’s easy to form effective Al doping in ZnO crystals.
AZO affiliates to n type doping of ZnO.

UV emission peaks were mostly affected by the influence of ZnO.
ZnO and SnO2 thin films were deposited as control samples.
The number of sprays was maintained at 90 for all samples.
Presence of ZnO and SnO2 peaks exhibit hexagonal wurtzite and tetragonal cassiterite structure, respectively which follow the JCPDS card no of 79-0208 and 77-0449, respectively.
El-Shall, Growth and characterization of ZnO, SnO2 and ZnO/SnO2 nanostructures from the vapor phase, Top.

Characterization includes FFA concentration, saponification number, iodine number and water content.
The diffraction peaks are in a good agreement with the standard pattern of CuO (JCPDS card NO. 050661).
The intensities and position of the peaks are in good agreement with standard of hexagonal wurtzite ZnO (JCPDS Card No. 36-1451).
In addition, the diffraction peaks of Al2O3 are still present and virtually unchanged against CuO and ZnO loading.
There are two series of diffraction peaks appeared corresponding to hexagonal wurtzite ZnO and monoclinic CuO.

These results are in good agreement with standard ZnO (JCPDS card No. 36-1451).
In the case of the 3% Ag/ZnO sample, an additional small peak at 2θ=38.8º marked with “*” is also created which is related with the face centered cubic phase of metal Ag NPs according to (JCPDS file No. 04-0783) [3], [12].
XRD diffraction peaks of pure ZnO, 3% Ag/ZnO, and 3% F-MWCNTs/ ZnO.
FTIR spectra of: a) ZnO, b) 3% Ag/ZnO, and, c): 3% F-MWCNTs / ZnO.
From eq. 2, increasing the numbers of ZnS molecules will lead to an increase in the sensitivity and the recovery time, while the response time will decrease because in desulfurization process ZnS molecules should be changed into ZnO again, according to Mortezaali and Moradi [23] and the following reaction: 2ZnS(s) + 3O2(g)desulfuration 2ZnO(s) + 2SO2(g) (3) Fig. 9.

Nitrogen Dioxide Gas Sensor of In2O3–ZnO Polyhedron Nanostructures Prepared by Spray Pyrolysis Jassim M.
The In2O3–ZnO system was extensively investigated by Moriga et al. [8].
This system contains many homologous compounds of the formula Znk In2Ok+1 (k=integer number) described as a structure with a k number of ZnO layers sandwiched between two In2O3 layers [9].
Polycrystalline structures correspond to cubic bixbyite In2O3, referring to JCPDS standard card No. 96-210-4744 with two broad peaks are located at 2θ of 30.50° and 51.04° corresponding to (222) and (440) diffraction peaks, respectively.
Dhahri et al., CO sensing characteristics of In-doped ZnO semiconductor nanoparticles, J.

Generally, in ZnO, electrons are promoted from the valence band and transferred to the conductance band under illumination that provides no less than the band gap energy of ZnO, leaving the corresponding number of holes in the valence band to form electron-hole pairs.[5] Photocatalysts oxidize organic polymers by adsorption holes.
With reference to the JCPDS card, it is found that our ZnO powder is of wurtzite structure, and it exhibits good crystallinity and purity.
Room temperature ultraviolet stimulated emission of ZnO nanocrystals, J.
Characterization of nanosized ZnO by thermal analysis, J.
XPS valence band of ZnO films, J.

Pre-heating at 100°C is the most favourable for highly oriented ZnO thin films along (002) plane whereas all films deposited with different number of layers are oriented along (101) plane.
Structure analysis The XRD patterns of the ZnO thin films (Fig. 2), as can be seen from (Fig. 2a), all detectable peaks can be ascribed to the ZnO Zincite-type structure (JCPDS card No. 01-073-8765).
Figure 4: EDX diagramme of ZnO thin film preheated at 100°C. 3.3 Optical properties The optical transmittance spectra of ZnO films deposited at varying pre-heating temperatures and number of layers are shown in Fig. 5.
The synergistic effects of the pre-heating temperature and the number of layers on structural, morphological, optical properties and photocatalytic activity of ZnO thin films are investigated.
Iratni, Structural, optical and photocatalytic properties of ZnO nanorods: Effect of aging time and number of layers, Ceramics International, 42 (2016) 9673-9685

The 0.1 ml sample of the treated solution was taken and spread onto a Nutrient Agar (NA) plate, each plate was incubated at 37ºC for 24 h, and the number of viable E. coli colonies were counted.
XRD results of the ZnO and WO3 co-doped VO2 nano-pigments with and without ZnO doping after annealing at 700ºC are shown in Fig. 1.
The 0.3 and 0.5 at% ZnO doped pigments exhibited monoclinic phase at 2q (degree) of 27.9, 33 and 36.2° while the 0.1 at% ZnO displayed an amorphous phase (JCPDS Card No. 82-0661, monoclinic, P21/C 14).
Samples Crystallite size (nm) Yield (%) VO2 Commercial grade 33.2 - Undoped 55.5 74 0.1 at% ZnO/WO3/VO2 Amorphous* 75 0.3 at% ZnO/WO3/VO2 33.7 75 0.5 at% ZnO/WO3/VO2 42.1 76 Transmission Electron Microscopy Analysis.
Samples Transition temperature Heating (ºC) Cooling (ºC) Undoped 66.25 61.15 0.1 at%ZnO/WO3/VO2 - * - * 0.3 at% ZnO/WO3/VO2 59.43 45.63 0.5 at%ZnO/WO3/VO2 52.60 43.73 (*Amorphous material, the results cannot be analysed.)

The intensity and number of diffraction peaks mainly depend on the amount of corresponding phases.
All the sharp diffraction peaks can be perfectly indexed with the standard JCPDS (24-1470) data.
The band positions and number of absorption peaks are depending on crystalline structure and chemical composition.
The number of peaks in the emission spectrum represents the wavelength of emission.
El-shall, Growth and characterization of ZnO, SnO2 and ZnO/SnO2 nanostructures from the vapor phase, Top.