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Room-Temperature ZnO Nanoparticle Ethanol Gas Sensors under UV Illumination S.
A zinc oxide (ZnO) nanoparticle gas sensor was formed by spin coating.
We found that all of the diffraction peaks of the ZnO nanoparticles and Al2O3 could be indexed to the wurtzite structures, ZnO and Al2O3, according to the standard JCPDS (no.897716 & no.751526) card.
XRD spectrum of ZnO nanoparticles on Al2O3 substrate.
Acknowledgements This work was supported by the National Science Council under contract number NSC 95-2221-E-006-314 and NSC 95-2221-E-006-357-MY3.

The crystallization of the ZnO hexagonal phase with a wurtzite structure and the ZnAl2O4 phase with a cubic structure occured according to (Joint Committee on Powder Diffraction Standards (JCPDS) PDF numbers 00-036-1451 and 01-073-1961 respectively) is noted.
The TC(hkl) values of our film (see Table 1) are calculated using the following formula [25]: (1) Where I(hkl) and I0(hkl) are respectively the relative intensity of the (hkl) peak and the standard intensity of the (hkl) peak given in the JCPDS cards, n is the number of diffraction peaks.
ZnO nanostructures can typically have a number of defects such as oxygen vacancies, lattice disruptions, etc.
From the figure 7(a) it is noticed that some diffraction peaks agree well with the standard pattern of ZnO phase (JCPDS card No. 36-1451), reflecting the (002) and (101) planes.
(ZnO, ZnAl2O4, Zn2SiO4 and Si(111) JCPDS, 36-1451, 01-073-1961, 37-1485 and 03-0549, respectively).

Among many properties of ZnO nanocrystals, the photoluminescence (PL) properties of ZnO nanocrystals have been widely studied by many researchers [2, 3].
Figure 2 shows XRD patterns of as-prepared ZnO nanocrystals.
The diffraction peaks indicate the nanocrystalline nature (JCPDS card no.36-1451).
XRD patterns of the sol-gel synthesized ZnO nanocrystals.
Acknowledgements This work was financially supported by the grant from Changzhou University under the contraction number ZMF1002132.

Moreover, the MEF performance of the Ag/ZnO composite depended on the deposited angle, firstly increasing and then decreasing with the tilt angle of Ag/ZnO core-shell structure.
Furthermore, the core-shell structure can be prepared by a number of methods, such as template-confined synthesis routes, high-temperature methods, hydrothermal synthesis et al [10].
The diffraction peaks, related to the (111), (200), (220), (311) reflections of cubic Ag phase, were observed obviously in fig1, corresponding to the standard PDF card (JCPDS no. 04-0783).
Fig.2 UV-Vis spectra of the Ag particles (a) and Ag/ZnO core-shell structure (b) Fig.3 showed the SEM image of the surface morphology of Ag/ZnO composite particles on the FTO.
Fig.6 (a) and (b) showed as the deposition Angle increases, the peak intensity increases and then decreases, because reducing the number the Ag as the deposition angle increases .The image clearly showed that both the Ag/ZnO core-shell structure and the Ag particles can enhance the emission of the dye.

ZnO and Co3O4 powders were employed as the precursors.
Numbers of studies both from experimental and theoretical approaches have been suggested the ferromagnetism on transition metal-doped ZnO.
The XRD peaks excellently agree with JCPDS card No. 75-0576.
Cao, Structure and ferromagnetic properties of Co-doped ZnO powders, J.
Deepak, Absence of ferromagnetism in Mn- and Co-doped ZnO, J.

Both FESEM and XRD results revealed that ZnO thin films were composed of hexagonal ZnO crystals in nanoscale dimensions.
ZnO it has a large number of technological applications including a variety of sensors, such as bio-molecule sensor [1], ultraviolet detecto r[2] and chemical and gas sensors [3].
The ZnO thin films were then annealed with furnace at 500°C for 2 hours as to get the crystallization of ZnO.
All the diffraction peaks in the result is according to the standard card (JCPDS 36-1451).
This is due to the sharp absorption edge of ZnO, which is very close to the intrinsic band-gap of ZnO (3.3eV) [11].

Porous films with very large internal surface area offer a number of intriguing features that are advantageous in the design of optoelectronic devices [5].
At high concentration, almost all ZnO seeds grew.
In other words, a pre-existing ZnO seed layer improved the growth of ZnO whiskers along the c-axis; lower concentration is beneficial for obtaining individual, smaller-diameter and high-density ZnO nanowhiskers without the dense middle layer.
Although all ZnO diffraction peaks are in good agreement with the JCPDS card (36-1451) for a typical wurtzite-type ZnO crystal (hexagonal, P63mc), a significantly higher intensity of 0002 diffraction peak indicates that ZnO nanowhisker films were preferentially orientated along the c-axis direction (grown along the direction perpendicular to the (0001) crystallographic face).
ZnO films served as the electron collecting electrode.

From above Fig. 4, it is clear that different peaks and troughs are recorded at different wave numbers.
The wave number shift to 541.53 cm -1 for 1.7wt % Cu doped ZnO Fig. 4b and to 456.17 cm -1 for 6.8wt % Cu doped ZnO Fig. 4c.
The peak positions in the Fig. 8 shows the formation of hexagonal wurtzite crystal structures, which are in very good agreement with the standard JCPDS Card No.00-005-0664.Cu doped ZnO also retains the hexagonal wurtzite crystal structure.
The JCPDS, file No. 04–0836 for copper, indicates peaks after 2θ= 30˚.
JCPDS card No. 38-0385 for Zn(OH)2, shows a peak at 2θ= 22.134˚ below 30˚.

All the anatase structure of TiO2 diffraction peaks can be found in No. 84-1286 card, rutile structure of TiO2 indexed in No. 86-0147 card, wurtzite structure of ZnO indexed in JCPDS card No.80-0075 and cubic phase of ZnTiO3 were well matched with JCPDS card No. 39-0190.
In this test the amounts of colonies are steady and after one hour the number of the bacteria colonies decreases and it takes some time for reactive species reach to the faraway bacteria.
Chemical reaction between bacteria and reactive species generated by TiO2 /ZnO (OH- and O2-).
Hahn” Optical and structural properties of ZnO/ TiO2/ZnO multi-layers prepared via electron beam evaporation” Vacuum 83 (2009) 878–882
Hadi Givianrad” The effect of different molar ratios of ZnO on characterization and photocatalytic activity of TiO2/ZnO nanocomposite” Journal of Saudi Chemical Society (2012)

All the diffraction peaks are attributed to the standard hexagonal structure of ZnO (JCPDS Card No. 5-664), which has wurtzite crystal structure with calculated lattice constants of a = 3.246 Å, c = 5.208 Å and hexagonal symmetry belonging to the P63mc space group.
Thus ZnO nanoflakes are apt to generate in the reaction system.
Schematic illustration of the formation process of ZnO nanospheres.
As the microwave-assisted process was accomplished under the air atmosphere, the crystalline nanoparticles composed of the ZnO spheres can generate a number of defects in the crystal structure.
The photoluminescence (PL) spectrum of the ZnO nanospheres.