Chemical Science Review and Letters ISSN 2278-6783 Che Sci Rev Lett 2012, 1(2), 62–77 Article CS01204207 62 Research Article Study of Structural and Dielectric Properties of Gold Embedded ZnO Nanohairs Fabricated by Thermal Oxidation Methods S. Srivastava Material Science & Metallurgical Engineering, Maulana Azad National Institute of Technology, Bhopal M.P. (India) Abstract Zinc oxide nano hair/needle was synthesized from the thermal oxidation of zinc metal at temperature range from 300-700 o C for 2hrs by controlling the oxygen partial pressure, the beautiful results give optimum information about the formation of ZnO nanostructures at the surface of metallic Zinc. In initial stage the developed structure was again modified by sequential and step wise heating of Zn-metal in open atmosphere. Each and every times, the thickness of the oxide becomes increase. This growth was catalyzed by the presence of the gold in the matrix. The morphology of the grown structure was investigated by SEM observation. Subsequent heating of the sample in open atmosphere, the sizes of growing needle of ZnO nanostructure becomes drastic change and elongated in those directions, where the heat transfer effect is nullified. At the higher temperature, the chance of oxidation is to be increase, because of higher rate constant of the nucleation. At this level, oxygen partial pressure plays very crucial role in nucleation of ZnO needle structure. The beautiful needle of ZnO with well separated from each other was obtained. This was identified by XRD and Raman investigation. At the higher temperature, the dielectric of the nanostructure are reported and also varied with annealing temperature. *Correspondence S. Srivastava Email: s.srivastava.mmsme@gmail.com Mobile number: +919479910003 Keywords: Thermal oxidation, Annealing, Nanohair/ Nanoneedle, Raman Spectroscopy. Introduction Zinc oxide, ZnO is a versatile semiconducting material with direct band gap (3.37 eV) and has high exciton binding energy (60 meV) has a great attention from silent feature in device fabrication such as light emitting diode, solar cells and various type of sensors [1-2]. ZnO as a Microwave dielectric ceramics, which have high permittivity, are used as materials of microwave components such as resonator, band pass filter and duplexer. These materials received attention due to the rapid progress in microwave telecommunications and satellite broadcasting etc. [3, 4]. The band gap of ZnO can be tuned via divalent substitution on the action to produce heterostructures. Cadmium, (Cd) doping can decrease the band gap to as low as ~ 3.0 eV, whereas Magnesium (Mg) doping can increase the band gap to as high as ~ 4.0 eV. Electron doping in nominally undoped ZnO has been attributed to Zinc interstitials, oxygen vacancies, or hydrogen. With appropriate dopants such as aluminum and galum, it is both transparent in the visible region and electrically conductive [5, 6]. For ZnO, n-type conductivity is relatively easy to realize via excess Zinc or with Aluminum (Al), Gallium (Ga), or Indium (In) doping, but p-type doping has only recently been achieved. This is a fairly common occurrence in wide band gap semiconductors, where difficulty in achieving bipolar “n-type and p-type” doping is not unusual. The most promising dopants for p-type material are the group V elements. Conductivity of ZnO is decreases when heated in oxygen under pressure and when heated in vacuum, its conductivity increases. The change in conductivity of Zinc oxide can also be caused by the addition of varying amounts of monovalent oxides decreases the conductivity whereas addition of trivalent oxides such as Aluminum (Al) or Chromium (Cr) increases the conductivity. Viorica Musat et al. reported the synthesis of ZnO 1D nanostructures grown on glass substrates seeded with gold layer, pre-prepared ZnO nanoparticles or sol– gel derived ZnO layer [7]. C. W. Cheng et al. observed six fold enhancements in the near band gap emission of ZnO nanorods by employing surface Plasmon of Au nanoparticles, while the defect-related emission is completely suppressed. Time-resolved photoluminescence indicates that the decay process becomes much faster by Au capping [8]. C. W. Lai et al. [9] described that the effects of metal coating on the near-band-edge emission of ZnO thin films have been studied by photoluminescence and atomic force