The influence of the pH on the electrolyte-SiO2-Si system studied by ion-sensitive fet measurements and quasi-static C-V measurements

The responses of ion-sensitive FETs (ISFETs) with thermally grown SiO2 gate regions and of electrolyte-SiO2-Si (EOS) structures to stepwise changes in the pH were studied.\ud \ud In addition to a change in the boundary potential at the electrolyte-SiO2 interface which accounts for the observed initial response of ISFETs, a mechanism is also proposed in which one or other hydrogen-bearing species interacts with the surface states at the SiO2-Si interface.\ud \ud This proposed mechanism is based on the observed time drift in the response of ISFETs and on the changes in the shape of the quasi-static C-V curves of the EOS structures

From conventional membrane electrodes to ion-sensitive field-effect transistors

The theory concerning conventional membrane electrodes is often used as a starting point for the theoretical description of the operation of an ion-sensitive field-effect transistor. Although this results in a useful description of the device, a better view of the principles, and consequently the possibilities, of the new ion-sensitive device may result if the analysis is carried out in more detail, especially with respect to measuring concepts. This is presented in the paper. A careful comparison between the operation of a conventional membrane electrode and the i.s.f.e.t. leads to a definite classification of different types of i.s.f.e.t.s. These types are illustrated with corresponding measurements. In addition, the most appropriate application for each type is mentioned

A data-driven model for valve stiction

The presence of nonlinearities, e.g., striction, hysteresis and backlash in a control valve limits the control loop performance. Striction is the most common problem in spring-diaphragm type valves, which are widely used in the process industry. Though there have been many attempts (EnTech, 1998; Gerry and Ruel, 2001; Horch and Isaksson, 1998; Taha et al., 1996; Piipponen, 1996; McMillan, 1995) to understand the stiction phenomena and model it, there is a lack of a proper model which can be understood and related directly to the practical situation as observed in a real valve in the process industry. This study focuses on the understanding, from real life data, of the mechanism that causes stiction and proposes a new data-driven model of stiction, which can be directly related to real valves. It compares simulation results generated using the proposed model with industrial data

Playing a quantum game with a corrupted source

The quantum advantage arising in a simplified multi-player quantum game, is found to be a disadvantage when the game's qubit-source is corrupted by a noisy "demon". Above a critical value of the corruption-rate, or noise-level, the coherent quantum effects impede the players to such an extent that the optimal choice of game changes from quantum to classical.Comment: This version will appear in PRA (Rapid Comm.

An investigation of the hydration properties of chemically vapour-deposited silicon dioxide films by means of ellipsometry

Time-dependent ellipsometric measurements were made of the water absoprtion in SiO2 films grown by chemical vapour deposition at low temperatures. These films were exposed to water vapour at different pressurures. We determined in the ellipsometric volume percentage of water in the oxide film from the changes in the ellipsometric parameters due to water absorption. We also obtained a diffusion coefficient of water of the order of 1.3 x 10-13 cm2 s-1. From the reversible changes in the ellipsometric parameters due to dehydration we conclude that the water is physically adsorbed

High resolution imaging of dielectric surfaces with an evanescent field optical microscope

An evanescent field optical microscope (EFOM) is presented which employs frustrated total internal reflection o­n a localized scale by scanning a dielectric tip in close proximity to a sample surface. High resolution images of dielectric gratings and spheres containing both topographic and dielectric information have been obtained. The resolution obtained is 30 nm in the lateral directions and 0.1 nm in height depending o­n proper tip fabricatio

A review of the utilisation of water hyacinth: alternative and sustainable control measures for a noxious weed

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