Studies on the control of ZnO nanostructures by wet chemical method and plausible mechanism

Abstract

This research article provides a pathway of controlled growth of ZnO nano-rods, -flowers, -needles or -tubes without external chemical catalysis, via a simple wet chemical method by control of synthesis temperature. Morphological effects on structural and optical properties are studied by Ultraviolet-visible (UV-vis) spectroscopy shows slight enhancement in the band gap, with increasing synthesis temperature. Photoluminescence (PL) data indicates the existence of defect in the nanomaterials, which is more elaborately explained by schematic band diagram. A sharp and strong peak in Raman spectroscopy is observed at ∼438cm−1 is assigned to the E2high optical mode of the ZnO, indicating the wurtzite hexagonal phase with high crystallinity.

Influence of ammonia concentration on the microstructure, electrical and raman properties of low temperature chemical bath deposited ZnO nanorods

“…We have observed slight peak shifts to lower frequencies with increasing ammonia concentration. The shifts can be attributed to spatial confinement, phonon localization and surface impurities as reported by Rana et al [29]. The full width at half maximum (FWHM)…”

“…4. The induced strain, ε, in the nanorods was calculated using the equation of Williamson and Hall [29].…”

Sr- and Ni-doping in ZnO nanorods synthesized by a simple wet chemical method as excellent materials for CO and CO2 gas sensing

“…The (002) reflection peak in Ni5ZO show a slight shift towards a lower value relative to undoped ZnO. Further, (100) and (101) planes diffraction peaks are prominent than (002) plane, which indicates the change in the orientation/morphology with increasing Ni doping 6 . For Sr-doped samples, there is increment in both a and c parameters because of large ionic radii of Sr 2+ (1.18 Å) than Zn 2+ .…”

“…The growth mechanism of ZnO was already discussed elsewhere 6 In order to evaluate the textural effects induced by the addition of dopants, the nitrogen adsorption-desorption isotherm and the corresponding Barrett-Joyner-Halenda (BJH) pore size distribution plot (see inset) of all samples are shown in Figure S1. Using the BJH method and the desorption branch of the nitrogen isotherm, the BET surface area (SA) have been calculated and are shown in Table 1.…”

Search for Origin of Room Temperature Ferromagnetism Properties in Ni-Doped ZnO Nanostructure

“…in a wide-gap semiconductors provides a conceivable means of tuning of both optical properties as well as ferromagnetism properties of a single material [8][9][10][11] . It also demonstrates that by simple change in the shape and size of nanomaterial it is possible to tune the physical properties of nanostructure [12][13][14] . However, present and existing theories and results [5][6][7] cannot satisfactorily articulate the origin of the witnessed ferromagnetism.…”