Search

Zinc oxide (ZnO) doped with Mn, Fe and Mn-Fe thin films have been deposited onto Si (1 0 0) by sputtering. The films have hexagonal wurtzite structure, the estimated crystallite (D) show decreases with change in doping in ZnO. The FE-SEM images show dense microstructure with an average grain size ∼22–32 nm. The AFM images ranges from ∼4 to 7 nm. The phonon modes of E (high) and A1 (LO) correspond to ZnO. The mode at 274 cm−1 was missing, indicating nitrogen is not present in ZnO. The films deposited for Mn-Fe co-doped ZnO show high intensity at mode of 964 cm−1 than Mn and Fe in ZnO, show different ionic radii of Mn and Fe.

The heat and mass transfer characteristics of the nonlinear, unsteady, radiative MHD boundary layer slip flow of a chemically reacting fluid past an infinite vertical porous plate are taken into account in this study. The effect of physical parameters are accounted for two distinct types of thermal boundary conditions namely prescribed uniform wall temperature thermal boundary condition and prescribed heat flux thermal boundary condition. Exact solution of the governing equations for the fluid velocity, temperature and concentration are obtained by using two term perturbation technique subject to physically appropriate boundary conditions. The expressions of skin friction, Nusselt number and Sherwood number are also derived. The numerical values of fluid velocity, temperature and concentration are displayed graphically whereas those of shear stress, rate of heat transfer and rate of mass transfer at the plate are presented in tabular form for various values of pertinent flow parameters. Results are compared with the literature in the limiting case.

Zn0.9Co0.1Oδ thin films have been deposited by radio frequency magnetron sputtering onto fused quartz substrates under oxygen gas environments as a function of film thickness (time duration). The as deposited films show hexagonal wurtzite structure of ZnO with films orientated in (0 0 2) plane perpendicular to base plane, without any secondary phases of CoO in host ZnO matrix. The crystallite (D) values estimated from XRD plots show increases with film thickness. The microstructural images recorded with field emission scanning electron microscopy (FE-SEM) have dense microstructure with an average grain size varies about ∼28–43 nm. The elemental composition of thin films were examined by energy dispersive spectroscopy confirms presence of Co in ZnO. The films have optical transmission in the visible region is about 55–70%, the absorption edge shifts towards low energy range with increase in film thickness. The estimated optical energy band gap of as deposited films shows a decreasing trend as a function of film thickness. The optical energy band gap for all the films are listed is varies about 3.42–2.85 eV respectively.

We fabricated a fourth generation glucose biosensor using CeO2@CuO core shell nano structure (CeCCS NSs). A simple leave extract of Ocimum tenuiflorum was used to prepare different wt% of 0.2, 04, 0.6, and 0.8 CuO (shell), above 1 wt% of CeO2 (core). The successful formation was confirmed by various characterization techniques like XRD, Uv–Vis, FTIR, SEM and HR-TEM. In the biosensor, 0.4 wt% of CeCCS NSs has shown efficient properties due to its high surface area. The good conductivity and high catalytic activity towards glucose sensing properties were estimated by screen-printed electrode (SPE). The ampherometric studies of CeCCS/SPE modified electrode have been optimized at potential + 0.4 V, showed a sensitivity of 3319.83 μAm M−1 cm−2 within detection limit of 0.019 μM. More significantly, modified electrodes performed excellently against anti-interference and anti-poisoned activity in glucose sample and exhibited promising results for the sustainable improvement for non-enzymatic sensing applications.

We fabricated a fourth generation glucose biosensor using CeO

Thin films of Mn-Fe co-doped ZnO deposited onto borosilicate glass substrates by rf-magnetron sputtering in argon gas pressure. The as deposited thin films show hexagonal wurtizite structure, without any secondary phases of Mn or Fe in host ZnO within XRD limit. The crystallite (D) of the films decreases with increase in argon working gas pressure. The field emission scanning electron microscope (FE-SEM) images show dense microstructure with increases in average grain size as a function of argon gas pressure are about ∼12 – 44 nm. The elemental composition of the as deposited thin filmswere confirmed by EDS spectra. The room temperature M-H plots show clear signature of ferromagnetic behavior with increase working gas pressure, the magnetic moment (Ms) of as deposited thin films is about 32 to 47 emu/cc as a function of working gas pressure. The increase in ferromagnetism in Mn-Fe co-doped ZnO thin films is due to coupled magnetic moments of multi atoms of Mn/Fe in host ZnO matrix.

Thin films of Co doped ZnO thin films have been deposited on fused quartz substrates by radio-frequency magnetron sputtering in mixed gas environment of Ar+ N2 with increase in nitrogen gas content in sputtering chamber up to 100%. The as deposited show the hexagonal wurtzite structure of ZnO with (002) peak along c-axis, without any indication of secondary phase of Co or N2 in ZnO matrix. The surface morphology of the films show dense microstructure. With increase in nitrogen gas composition the films show decrease in average grain size for as deposited films. The room temperature transmittance spectra of as deposited films varies about ∼92-87% show decrease with increase in nitrogen in the films. The estimated direct band gap of the films varies in the range between 4.91 -3.75 eV. The band gap show decrease with increase in nitrogen component in the films is attributed that nitrogen acts as dopant in ZnO matrix along with Co in host ZnO matrix.

ZnO thin films were deposited on quartz substrates by RF sputtering under argon, oxygen and nitrogen gas environment. The as deposited films showed hexagonal wurtzite structure with (002) orientation along c-axis. The mechanical properties of films with thickness ranging from 842[Formula: see text]nm to 1067[Formula: see text]nm and grain size 94–124[Formula: see text]nm were studied using nanoindentation technique. The Young’s modulus and hardness of the films were in the range 76–257[Formula: see text]GPa and 5–18[Formula: see text]GPa, respectively. Both parameters decreased with increase in indentation depth of the films. The spatial distribution of these parameters were strongly dependent on the gas environment used for film deposition.