S. N. Sarangi; V. Siva; B. K. Padhi; P. K. Sahoo
Abstract
We report the fabrication and characterization of photosensitive heterostructure device using pure and Cu doped ZnO nanorods on n-Si substrate using a low cost hydrothermal technique. Special techniques like Rutherford backscattering spectroscopy and Proton Induced X-ray emission (PIXE) were used to ...
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We report the fabrication and characterization of photosensitive heterostructure device using pure and Cu doped ZnO nanorods on n-Si substrate using a low cost hydrothermal technique. Special techniques like Rutherford backscattering spectroscopy and Proton Induced X-ray emission (PIXE) were used to confirm the doping of Cu in ZnO nanorods. The PIXE measurements confirm the absence of any foreign element in parts per million level, except pure Cu doping in ZnO. The compressive stress in (002) peak develops after Cu doping is indicating the successful substitution of Cu +2 ions into Zn +2 lattice sites. The I-V measurement of 5% Cu doped ZnO device shows five orders of magnitude increase in current flow compared to 1% Cu doping. Under ultraviolet (UV) light exposure further enhancement of the photocurrent in the devices has been observed, which demonstrates the capability of Cu doped ZnO nanorods as a potential UV photodetector.
Nidhi Chauhan; Utkarsh Jain
Abstract
The glucose level measurement in the blood of diabetic patients without significant variations is important. The level of glycated hemoglobin (HbA1c) in the blood provides an authentic tool for glucose level measurement. In our study, a biosensing system established on properly aligned single-crystal ...
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The glucose level measurement in the blood of diabetic patients without significant variations is important. The level of glycated hemoglobin (HbA1c) in the blood provides an authentic tool for glucose level measurement. In our study, a biosensing system established on properly aligned single-crystal zinc oxide (ZnO) nanorods structures grown on indium-tin oxide coated glass plate (ITO) electrode. ZnO nanorods were immobilized with fructosyl amino-acid oxidase (FAO) enzyme through physical adsorption integrated with cross linking molecules N-5-azido-2-nitro-benzoyloxysuccinimide (ANB-NOS). Whole blood samples were first hemolyzed & then properly digested with protease prior to measuring the HbA1c through the sensor. This enzyme biosensor reported an optimum response at +0.2 V. This biosensor displayed a significant sensitivity and detection limit (0.1μM), fast response time (4s) and wide linear range (from 0.1 to 2000 μM). The enzyme/working electrode is stable for about 4 months, when kept at 4 oC. This recommended biosensor method may apply for detecting HbA1c in blood samples obtained from apparently healthy as well as diabetic patients.
Berrin Ikizler; Sumer Peker
Abstract
The damage given to the ZnO nanorod coating immobilized at the bottom of a rectangular channel by water flow is assessed in this work. The experiments were conducted in complete darkness to determine the inherent stability of the nanorod coating without the interfering effect of UV radiation. The quality ...
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The damage given to the ZnO nanorod coating immobilized at the bottom of a rectangular channel by water flow is assessed in this work. The experiments were conducted in complete darkness to determine the inherent stability of the nanorod coating without the interfering effect of UV radiation. The quality and morphology of the nanorod arrays before and after use were determined by x-ray diffraction, scanning electron microscopy; rod breakage, by dynamic light scattering; and the extent of erosion, by concentration and weight measurements. The effect of pH of the flowing water in the range 4£pH10, and the effect of the volumetric flow rate in the range, 3.3-33 cm 3 /s are investigated in this work as parameters. ZnO erosion reaches a low-level plateau in the pH range of 6£pH£10. Within this range, water velocity and alignment of the nanorods control the extent of dissolution. Dissolution of ZnO nanorods essentially takes place on the polar (0001)-Zn plane of ZnO, resulting in the formation of serrated surfaces. Furthermore, inclined rods joining at the top surface is subjected to further dissolution through pit formation originating at the junction interface, and extending outwards. ZnO nanorod arrays could be used as a photocatalyst in the photocatalytic water treatment processes, where the dissolution from nanorods is in the range of 2.0−2.5 wt% after 24 h of operation under a flow rate of 3.30 cm 3 /s (≈12 L/h), well under the requirements of World Health Organization.
Yuvaraj Sivalingam; Arnaldo D Amico;Corrado Di Natale; Gabriele Magna; Giuseppe Pomarico; Eugenio Martinelli; Roberto Paolesse
Abstract
Recent studies suggest that the gas sensitivity of porphyrin-functionalized ZnO nanorods can be activated under visible light illumination. Then the use of properly coloured light tuned to the absorbance spectra of individual porphyrins could enable a control of sensors sensitivity. The effect of light ...
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Recent studies suggest that the gas sensitivity of porphyrin-functionalized ZnO nanorods can be activated under visible light illumination. Then the use of properly coloured light tuned to the absorbance spectra of individual porphyrins could enable a control of sensors sensitivity. The effect of light on the sensitivity to gases is critically governed by the transport phenomena of electronic charge across the interfaces of organic and inorganic structures. Therefore, accurate measurements of energy levels and contact potential differences in porphyrins functionalized ZnO nanorods are important to intepret the sensing properties of such hybrid materials. For the scope, Kelvin probe measurements of porphyrin-ZnO structures were performed exposing the material in dark and visible light and to organic vapours. Results provide an experimental basis to understand the mutual effects of gas adsorption and illumination to the device conductivity.