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Abstract: We analyzed 1/f noise in silicon nanowire ion-sensitive field-effect transistors (SiNW-ISFETs) having different wire widths ranging from 100nm to 1μm and operated under different gating conditions in order to determine the noise source and the sensor accuracy. We find that the gate-referred voltage noise S VG (power spectral density) is constant over a large range of SiNWs resistances tuned by a DC gate voltage. The measurements of S VG for SiNWs with two different gate-oxide thicknesses, but otherwise similar device parameters, are only compatible with the so-called trap state noise model in which the source of 1/f noise is due to trap states residing in the gate oxide (most likely in the interface between the semiconductor and the oxide). S VG is found to be inversely proportional to the wire width for constant wire length. From the noise data we determine a sensor accuracy of 0.017% of a full Nernstian shift of 60mV/pH for a SiNW wire with a width of 1μm. No influence of the ions in the buffer solution was found. [Copyright &y& Elsevier]

Abstract: We carried out selective area metal-organic vapor phase epitaxy (SA-MOVPE) of In-rich In x Ga1− x As/InP modulation-doped heterostructures in an N2 atmosphere. The aim is to obtain wire structures which exhibit strong spin–orbit coupling without using etching of the heterostructures for their fabrication. The wire geometry was studied as a function of mask opening width. The transport properties were determined at 0.5K and up to 10T magnetic field. A clear growth enhancement was confirmed as the initial opening width decreases; thus, the InGaAs as well as the total thicknesses became larger. Moreover, we confirmed the top width saturates in some narrower wires due to geometrically limited growth by facets. Some narrower wires showed high resistivity, which might originate from structural deterioration in In0.77Ga0.23As due to the growth enhancement and/or non-uniformity of the parallel wires. On the other hand, wider wires showed Shubnikov–de Haas (SdH) oscillations, which exhibited SdH beating patterns. All in all it is possible to achieve strong spin–orbit coupling in In x Ga1− x As/InP wires produced by SA-MOVPE. [Copyright &y& Elsevier]

Abstract High quality gratings are among the key elements for successful imaging with X-ray grating interferometry. Grating fabrication, specifically of absorption gratings, with high aspect ratio and large area, is a great challenge from a microfabrication point of view. In this paper the fabrication of absorption gratings by seedless electroplating of gold in high aspect ratio silicon moulds that are fabricated by deep reactive ion etching (Bosch process) is presented. We report on our latest results and discuss the possibility of reducing the grating period down to 1.3 μ m. In addition, the quality of the gratings is assessed by performing visibility measurements and imaging various samples on a compact in house X-ray grating interferometer. [ABSTRACT FROM AUTHOR]