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In this paper, we propose a UV-A sensor based on a 6H-SiC Schottky photodiode with a thin Ni2Si front electrode and an integrated hydrogenated silicon nitride (SiN:H) dielectric filter. 6H-SiC prototypes were fabricated by using a manufacturing process to a large extent already implemented on 4H-SiC poly-type for the realization of a high signal-to-noise ratio ultraviolet (UV) sensor already commercialized. The results obtained on 6H-SiC prototypes show optimal electrical performance with dark current density lower than 0.2 nA/cm2 at room temperature and 10 V reverse bias. The use of 6H polytype allows shifting of the UV sensor response from 290 nm peak responsivity wavelength measured on standard 4H-SiC photodiodes to 360 nm wavelength in 6H-SiC prototypes with an integrated SiN:H filter exactly in the middle of the UV-A band (320-400 nm) with a simultaneous consistent reduction of the optical response in UV-C and UV-B regions below 320 nm wavelength.

The development of integrated sensors is a challenge currently facing biodiagnostics where multiplexing and high sensitivity detection are frequently required. This work follows an approach based on silicon photomultiplier detection, phosphorescent nanobeads and compact front-face light-source configuration. The advantages of this approach also derive from the sensitivity, compactness, robustness and low operating voltage of SiPM devices. An experiment was performed to demonstrate performance in terms of sensitivity, with the results allowing the estimation of a detection limit for proteins of 1–10 pg/mL.

Denoting with 'nanodevice' any device with size in one dimension at least in the nanometre length scale (NLS), the basic constituent of integrated circuits (ICs), the metal-oxide-semiconductor (MOS) field-effect transistor (FET), is by several years a nanodevice. In fact, the thickness of the SiO"2 gate dielectric is around 3nm for logics or 5nm for nonvolatile memories. However, since the factors limiting the IC integration are horizontal sizes, in electronics one speaks of nanodevice when its size in one horizontal dimension at least is in the NLS. The definition of features in the NLS is impossible via optical lithography, but can be done using electron- or ion-beam lithography. These techniques, however, are very expensive and still in their fancy, at least for what concerns their exploitation in the industry practice. Geometries in the NLS can however be produced with relative ease by the spacer patterning technique, i.e., transforming vertical features (like film thickness) in the vicinity of a step of a sacrificial layer into horizontal features. The ultimate length producible in this way is controlled by: the steepness of the step defining the sacrificial layer; the uniformity of the deposited or grown films; and the anisotropy of its etching. While useful for the preparation of a few devices with special needs, the above trick does not allow by itself the development of a nanotechnology, where each layer useful for defining the FET should be in the NLS and aligned on the underlying geometries with tolerances in the NLS. Setting up such a nanotechnology is a major problem which will involve the IC industry in the post-Roadmap era. Irrespective of the detailed structure of the basic constituents of nanoICs (molecules, supramolecular structures, clusters, etc.), any nanoIC can hardly be prepared without the ability to produce arrays of conductive strips with pitch in the NLS. This work is devoted to describe a scheme (essentially based on the existing microelectronic technology) for their production without the use of electron- or ion-beam lithography and used as host of molecular devices.

An experimental study via X-ray photoelectron spectroscopy at different takeoff angles of the derivatization of atomically flat, hydrogen terminated, 1 × 1 (1 0 0) Si surfaces with 1-octyne is reported. The major conclusion of the experimental analysis (that a large fraction of the grafted moieties contain unreacted π bonds) is then compared with the results of high-level ab initio modelling with model molecules of the derivatization act.

Hydrogen-terminated, atomically flat, 1×1 (un)reconstructed, (100)-oriented, silicon surfaces have been functionalized with 1-octyne and then studied via X-ray photoelectron spectroscopy. The C 1s signal shows that the addition of the hydrocarbon chain occurs through the formation of environmentally stable Si-C bonds, in agreement with hydrosilation as the major grafting route.

An X-ray photoemission spectroscopy (XPS) study at different takeoff angles of the derivatized surface resulting after prolonged (2 h) exposure of hydrogen-terminated 1×1-reconstructed (100)-oriented silicon to liquid 1-octyne at 170 °C has been carried out. The experimental data may be interpreted assuming that: (1) the grafting occurs through the formation of Si–C bonds; (2) in the considered conditions, one π bond of the octyne has a large survival probability after the grafting; and (3) side reactions leading to Si–O–C or Si–C(O) moieties are also active.

An experimental study of the Si 2p XPS spectrum at different take-off angles of atomically flat, hydrogen-terminated 1 × 1 Si(100) is reported. The observed spectrum can be described accurately by considering three additional contributions to the spectrum of elemental silicon. Each contribution is attributed to a chemical state of silicon on the basis of its chemical shift with respect to elemental silicon and the depth of the region where it was originated. Copyright © 2003 John Wiley & Sons, Ltd.

This work presents an experimental study based on X-ray photoemission spectroscopy (XPS) of hydrosilation of 1-alkyne as a tool for the functionalization of the (100) surface of silicon. In particular, the following processes are considered: (i) hydrogen termination of silicon via HF etching and subsequent exposure to H2 at high temperature, and (ii) grafting alkene chains to the resulting hydrogen-terminated surface via hydrosilation of 1-octyne.

Silicon oxide and silicon nitride surfaces have been treated with 1-octadecene at ∼200°C. The resulting film topography has been inspected by atomic force microscopy (AFM), showing a densely packed organic coating with a corrugation of some tenths of a nanometre. High-mass-resolution time-of-flight secondary ion mass spectrometry (ToF-SIMS) spectra from such surfaces display octadecene- as well as substrate-related peaks. Furthermore, peaks diagnostic of the formation of SiOC or SiC linkages are observed in the case of silicon oxide, whereas the same peaks and those due to SiNC species have been observed in the case of silicon nitride. These results suggest that 1-octadecene molecules are chemisorbed on the substrate. Contact angle measurements and AFMforce spectroscopy measurements allow comparison upon the macroscopic and nanoscopic scale, respectively, of the surface free energy modification due to the formation of the organic coating.

In this work, we report on the improvement of microarray sensitivity provided by a crystalline silicon substrate coated with thermal silicon oxide functionalized by a polymeric coating. The improvement is intended for experimental procedures and instrumentations typically involved in microarray technology, such as fluorescence labeling and a confocal laser scanning apparatus. The optimized layer of thermally grown silicon oxide (SiO(2)) of a highly reproducible thickness, low roughness, and fluorescence background provides fluorescence intensification due to the constructive interference between the incident and reflected waves of the fluorescence radiation. The oxide surface is coated by a copolymer of N,N-dimethylacrylamide, N-acryloyloxysuccinimide, and 3-(trimethoxysilyl)propyl methacrylate, copoly(DMA-NAS-MAPS), which forms, by a simple and robust procedure, a functional nanometric film. The polymeric coating with a thickness that does not appreciably alter the optical properties of the silicon oxide confers to the slides optimal binding specificity leading to a high signal-to-noise ratio. The present work aims to demonstrate the great potential that exists by combining an optimized reflective substrate with a high performance surface chemistry. Moreover, the techniques chosen for both the substrate and surface chemistry are simple, inexpensive, and amenable to mass production. The present application highlights their potential use for diagnostic applications of real clinical relevance. The coated silicon slides, tested in protein and peptide microarrays for detection of specific antibodies, lead to a 5-10-fold enhancement of the fluorescence signals in comparison to glass slides.