The surface chemistry of n-type Si electrodes that had been etched, exposed to electrolyte, and electrochemically cycled has been probed using high-resolution X-ray photoelectron spectroscopy (XPS). n-Si surfaces etched in hydrofluoric acid-ethanol solutions (in air or N, ambients) displayed spectra in the Si 2p region that were free of detectable substrate oxide signals (15 X lo-" mol cm-, SO,; equivalent to 14% of a monolayer). Exposure of HF-C2H50H etched or of 49% HF(aq) etched n-Si surfaces to an electrolyte solution containing CH30H, dimethylferrocene (Me2Fc), and dimethylferricenium (Me2Fc+) generated very low levels, 1 ( 2 f 1) X mol cm-2 of silicon suboxides. Only sub-monolayer levels of SiO,, (4 f 2) X mol cm-2, were detected after electrochemical cycling of illuminated n-Si anodes in contact with CH30H-Me2Fc+/0 electrolytes. Even n-Si photoanodes maintained at short circuit with the CH30H-Me2Fc+/0 electrolyte for substantial periods (> 1000 C cm-, anodic charge passed) formed less than a single monolayer of strained Si02 at the silicon surface. Deliberate anodization of the Si surface in these electrolyte solutions yielded controlled amounts of thicker (8-10 A) Si02 overlayers; these overlayers provided a useful oxide for the formation of high-performance metal-insulatorsemiconductor device structures. These studies demonstrate that HF-C2H50H-or HF(aq)-etched n-Si surfaces are remarkably resistant to oxide formation during photoelectrochemical cycling in CH30H-based electrolytes, and that the outstanding photoelectrochemical Z-Vproperties of the n-Si/CH30H-Me2Fc+/0 junction are not a result of formation of passivating oxide overlayers on the Si surface.

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This paper explores gold nanoparticle (GNP) modified copper oxide nanowires(CuO NWs)based electrode grown on copper foil for non-enzymatic glucose detection in a wide linear ranging up to 31.06 mM, and 44.36 mM at 0.5 M NaOH and 1 M NaOH concentrations. The proposed electrode can be used to detect a very low glucose concentration of 0.3 µM with a high linearity range of 44.36mM and sensitivity of 1591.44 µA mM−1 cm−2. The electrode is fabricated by first synthesizing Cu (OH)2 NWs on a copper foil by chemical etching method and then heat treatment is performed to convert Cu (OH)2 NWs into CuO NWs. The GNPs are deposited on CuO NWs to enhance the effective surface-to-volume ratio of the electrode with improved catalytic activity. The surface morphology has been investigated by XRD, XPS, FE-SEM and HR-TEM analysis. The proposed sensor is expected to detect low-level of glucose in urine, and saliva. At the same time, it can also be used to measure extremely high sugar levels (i.e. hyperglycemia) of ~ 806.5454 mg/dl. The proposed sensor is also capable of detecting glucose after multiple bending of the GNP modified CuO NWs electrode. The proposed device is also used to detect the blood sugar level in human being and it is found that this sensor’s result is highly accurate and reliable.

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