Martin Donoval

Influence of surface oxidation on plasmon resonance in monolayer of gold and silver nanoparticles

Surface plasmon resonance of gold and silver nanoparticle (NP) layers is investigated by the experiment as well as simulations. Although the good agreement was found for gold NP film, a significant mismatch in the resonance energy for silver NP film was observed. The deviation was assigned to the presence of silver oxide (Ag2O) in silver NPs. As an alternative to the NP size-dependent Drude model, the analysis based on effective medium approximation for refractive index of Ag-Ag2O material system is carried out and compared with the core-shell model. Both Mies model and numerical simulation results illustrate shift of the surface plasmon resonance due to silver NP surface oxidation.Surface plasmon resonance of gold and silver nanoparticle (NP) layers is investigated by the experiment as well as simulations. Although the good agreement was found for gold NP film, a significant mismatch in the resonance energy for silver NP film was observed. The deviation was assigned to the presence of silver oxide (Ag2O) in silver NPs. As an alternative to the NP size-dependent Drude model, the analysis based on effective medium approximation for refractive index of Ag-Ag2O material system is carried out and compared with the core-shell model. Both Mies model and numerical simulation results illustrate shift of the surface plasmon resonance due to silver NP surface oxidation.

Plasmonic properties of Au-Ag nanoparticles: Distinctiveness of metal arrangements by optical study

The core-shell arrangement of binary compound plasmonic nanoparticles (NPs) is usually verified by plasmonic extinction spectra, since microscopy-based methods cannot provide analysis of many NPs. Here, we discuss possible scenarios of different metal arrangements: (i) core-shell model, (ii) bimetallic model, and (iii) mixture of pure metal NPs. The possibility of distinguishing individual cases is discussed in accordance with numerical simulations and an alternative characterization is suggested.

Biomedical signal amplifier for EMG wireless sensor system

This work presents differential amplifier designated as a part of modular biomedical sensor system (MBSS) used for EMG (electromyography) signal measurements. Except the standard features which characterize this type of device (high gain, low noise), some special requirements comprising very low supply voltage and low power consumption could be reached by application of the described amplifier. The amplifier provides switch-able 60/80dB gain at 15 Hz – 1kHz frequency bandwidth. A fourth order anti-aliasing filter for next processing block (AD converter) is included as well.

Behavior of various geometry MagFET structures

This paper deal with characterization of various MagFET structures in alternating magnetic field in frequency range from 20 Hz to 5 kHz. 2D numerical simulation of MagFET structures has been used to investigate current density distribution and influence of MagFET geometry to the external magnetic field sensitivity. Rectangle- and sectorial-shaped structures of various dimensions were designed and fabricated in standard 1μm two metal CMOS technology. Fabricated MagFET devices were characterized for applications as a sensor of external magnetic fields. The measurement results show dependence of MagFETs external magnetic field sensitivity on structure geometry, dimensions and biasing conditions.

Effective 3-D Device Electrothermal Simulation Analysis of Influence of Metallization Geometry on Multifinger Power HEMTs Properties

In this brief, obtained results of the electrothermal analysis of multifinger power high-electron mobility transistors (HEMTs) are presented. The analysis of thermal and electrical behavior is supported by effective 3-D electrothermal device simulation method developed for Synopsys TCAD Sentaurus environment using mixed-mode setup. The effects of multifinger HEMT structure metallization layout design are described and studied. Simulation results depict the significant effect of metallization geometry on the electrothermal properties and behavior of the power multifinger HEMTs.

Wearable healthcare electronics for 24-7 monitoring with focus on user comfort

Human health is important for people in any age. Healthcare addresses a market of more than 10% of the European gross domestic product. An ageing population will have an enormous impact on society and the economy. The objective of this article is to provide a view of some latest research innovations in field of bioelectronics. Among these a short description of non-invasive hydration sensor, glucose sensor, hemodynamic sensor preparation and implementation methods is provided followed by a proposal of a design of flexible plaster for ECG monitoring in function of a heart holter. A design of remote sensing units requires consideration of several functional blocs with following integration and evaluation phase. For the integration of such system several functional blocks are needed for the preparation of medical smart system cluster, such as energy source or harvester with supercaps or battery, communication (integrated antennas), new organic materials or biocompatible housing. Preparation of such system is deeper described by the example of an ECG plaster holter.

Electrode configuration for EMG measurements

This paper explains problematic of EMG (electromyography) signal measurements. Described experiments are partition of complex project “MEDISYS” dedicated to design of modern medical equipment, consisting the latest technologies and IC. The design is based on low noise wireless measurement block (for ECG, EMG and EEG monitoring) followed by actuator block with mechanical constructions and control electronic.

Characterization of MagFET structures

The paper deals with characterization of various MagFET structures in alternating magnetic field in frequency range from 10 Hz to 10 kHz. 3D numerical simulation of MagFET structures has been used to investigate influence of MagFET geometry to the magnetic field sensitivity. Rectangle shaped structures of various dimensions were fabricated in standard 1mum two metal CMOS technology. MagFET devices were characterized for applications as a sensor of external magnetic fields and also as a current monitor. The measurement results show dependence of MagFETs sensitivity on structure geometry, channel type and biasing conditions.

On-chip supply current monitoring units using magnetic force sensing

A built-in on-chip current sensors design based on magnetic force of is presented. The proposed sensors are aimed to be used for on-chip current testing in deep-submicron circuits with ultra low-voltage power supply. The advantage of the proposed monitors is mainly elimination of the undesired supply voltage reduction, commonly created by standard current test methods. Description of different sensor architectures, their designs and physical implementations on chip are presented. All the sensor versions were designed in 1.0 mum BiCMOS technology.

Analysis of Novel MagFET Structures for Built-in Current Sensors Supported by 3D Modeling and Simulation

Novel built-in current sensor structures based on selected electrophysical properties of a magnetic FET (MAGFET) is presented. The proposed sensor structures may be used for on-chip current testing in deep-submicron circuits with ultra low-voltage power supply. Their advantage is mainly in elimination of the undesired supply voltage reduction on the current monitor, commonly created by standard current test methods. Analysis of the influence of various device structures and dimensions on their electro-physical parameters and electrical characteristics is presented. All versions of MAGFET structure were designed using design rules of 1mum BiCMOS technology.