Potentiality of zinc oxide nanosensor prepared by a new electroplating method on p-Si (1 1 1) wafer substrate

Nanostructured ZnO thin films were deposited on p-Si (1 1 1) substrates using a new electrodeposition method. Electrical and sensing properties were investigated. Variations of the resistance measured between two points of the ZnO film, have shown a maximum sensitivity (δ = 10) in the presence of gas ‹CO› and (δ = 14,70) in the presence of ‹C2H5OH› at a temperature of 300 °C. Therefore, we can say that the sensitivity tests indicate that the sensor consisting of a nanometer zinc oxide layer is more efficient at temperatures beyond 100 °C. Moreover, the sensing element has demonstrated a good response to reducing gases species. Keywords: Electrodeposition, ZnO, Ethanol/carbon monoxide sensor, Response/recovery times, Sensitivit

Growth and characteristics of ZnO nano-aggregates electrodeposited onto p-Si(1 1 1)

In this paper we study nanocrystalline zinc oxide thin films produced by oxidation of electrodeposited zinc nanolayers on a monocrystalline p-Si(1 1 1) substrate. The electrolyte used is ZnCl2, an aqueous solution of 4 × 10−2 mol/l concentration. Several deposits were made for various current densities, ranging from 13 mA/cm2 to 44 mA/cm2, flowing through the solution at room temperature. A parametric study enabled us to assess the effect of the current density on nucleation potential and time as well as zinc films structure. The grazing incidence X-ray diffraction (GIXD) revealed that both Zn and ZnO films are polycrystalline and nanometric. After 1-h oxidation of zinc films at 450 °C in the open air, the structural analyses showed that the obtained ZnO films remained polycrystalline with an average crystal size of about 47 nm and with (1 0 0), (0 0 2) and (1 0 1) as preferential crystallographic orientations

Growth and characterization of thin ZnO films deposited on glass substrates by electrodeposition technique

Electrodeposition technique was used in order to produce nanometric zinc oxide films on glass insulating substrates. The effect of electrolyte concentration and applied current density on the formation and growth of electrodeposited Zn thin films in aqueous solutions of ZnSO4 were studied. After a thermal oxidation, a characterization of the structural morphology of the films deposited was carried out by optical microscopy (OM), atomic force microscopy (AFM), scanning electron microscopy (SEM) and by grazing incidence X-rays diffraction (GIXD). These characterization techniques show that the grains size of the films after oxidation at temperature 450 °C is between 5 and 15 nm, as well as the structure is polycrystalline nature with several orientations. UV/vis spectrophotometry confirms that it is possible to obtain transparent good ZnO films with an average transmittance of approximately 80% within the visible wavelength region, as well as the optical gap of obtained ZnO films is 3.17 eV