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Article
Publication date: 11 January 2018

Piotr Firek, Michal Cichomski, Michal Waskiewicz, Ireneusz Piwoński and Aneta Kisielewska

The purpose of this paper is to present possibility of fast and certain identification of bovine serum albumin (BSA) by means of ion-sensitive field effect transistor…

Abstract

Purpose

The purpose of this paper is to present possibility of fast and certain identification of bovine serum albumin (BSA) by means of ion-sensitive field effect transistor (ISFET) structures. Because BSA can cause allergic reactions in humans, it is one of reasons for development of sensitive sensors to detect residual BSA. BSA is commonly used in biochemistry and molecular biology in laboratory experiments. Therefore, to better understand the mechanism of signal transduction in simulated biological environment and to elucidate the role of adsorption of biomolecules in the generation of a signal at the interface with biological systems, the measurements of ISFET current response in the presence of BSA as a reference protein molecule were performed.

Design/methodology/approach

To fabricate transistors, silicon technology was used. The ISFET structures were coupled to specially designed double-side printed circuit board holder. After modification of the field effect transistor (FET) device with 3-aminopropyltriethoxysilane (APTES), a sensor with high sensitivity toward reference biomolecules was obtained. The current–voltage (I-V) characteristics of structures with and without gate modification were measured. Keithley SMU 236/237/238 measurement set was used. Deionized water solution and 0.05 per cent BSA were used.

Findings

In this research, a method of preparation of a biosensor based on a FET was developed. Sensitivity of APTES-modified FET device toward BSA as a biomolecule was investigated. I-V relationships of FET devices (with and without modification), being the effect of the interactions with the solution containing 0.05 per cent BSA, were measured and compared to the measurements performed for solutions without BSA.

Originality value

Compared to SiO2-containing ISFETs without modification or other different dielectrics, the application of APTES as the part of the membrane induced significant increase in their sensitivity to BSA.

Details

Circuit World, vol. 44 no. 1
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 2 January 2018

Rawad Elias, Pierre Ziade and Roland Habchi

The purpose of this paper is to investigate and classify the defects on silicon-based power devices under extreme conditions.

Abstract

Purpose

The purpose of this paper is to investigate and classify the defects on silicon-based power devices under extreme conditions.

Design/methodology/approach

Electrical characterization was performed on MOS devices to study their interface defects. The devices were subjected to a voltage or a current constraint to induce defects, and then measurements were done to detect the effects of those defects. Measurements include current voltage, capacitance and conductance characterization. The Hill–Coleman method was used to calculate the interface states density in each case.

Findings

It was found that most of the defects have energies within the upper band gap of the semiconductor.

Originality value

The method used in this paper allows the determination of any interface defects on a Si/SiO2 structure.

Details

Microelectronics International, vol. 35 no. 1
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 13 August 2019

Vitaliy Bilovol, Claudio Barbon and Bibiana Arcondo

The purpose of this paper is to investigate electrical properties of eutectic In8Sb8Te84 and In10Sb51Te39 as made thin films to evaluate their potential for non-volatile…

Abstract

Purpose

The purpose of this paper is to investigate electrical properties of eutectic In8Sb8Te84 and In10Sb51Te39 as made thin films to evaluate their potential for non-volatile phase-change memories, once the thermal measurements are very optimistic.

Design/methodology/approach

The films were deposited by pulse laser deposition technique. By using a very simple home-made cell, transversal current-voltage curves films were measured involving both voltage controlled-pulses generator and current controlled-pulses generator, employing different pulse shapes: triangular and sine shaped.

Findings

The memory effect, characteristic of a typical phase-change memory material, was observed in both materials under research. For higher tellurium content in the film, lower is the value of threshold voltage.

Research limitations/implications

Further studies on endurance, scaling and SET/RESET operations are needed.

Practical implications

The values of the key parameters, threshold voltage and hold voltage are comparable with those of Ge2Sb2Te5, GeTe and Sb2Te being considered to date as the main compounds for PCM devices.

Originality/value

The conduction mechanism in the amorphous regime is agreed with Poole–Frenkel effect in deep traps.

Details

Microelectronics International, vol. 36 no. 4
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 25 January 2011

L.S. Chuah, Z. Hassan, S.S. Tneh and S.G. Teo

The purpose of this paper is to demonstrate the n‐ZnO/p‐Si Schottky photodiodes.

Abstract

Purpose

The purpose of this paper is to demonstrate the n‐ZnO/p‐Si Schottky photodiodes.

Design/methodology/approach

A Zn film was deposited on silicon substrate by dc sputtering deposition technology from high purity zinc (Zn) targets. Then, the Zn films were then annealed under flowing oxygen (O2) gas environment in the furnace. ZnO nanorods morphologies have been successfully prepared through a simple method. No catalyst is required.

Findings

The structures and morphologies of the products were characterized in detail by using X‐ray diffraction, energy dispersive X‐ray, and scanning electron microscopy (SEM). According to experimental results, the current‐voltage characteristics of the device show the typical rectifying behaviour of Schottky diodes. The UV photocurrent measurement was performed using an UV lamp under a reverse bias.

Originality/value

The paper demonstrates that the n‐ZnO/p‐Si diodes exhibit strong rectifying conduct described by the current‐voltage (I‐V) measurement under a dark and illumination conditions.

Details

Microelectronics International, vol. 28 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

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Article
Publication date: 7 August 2017

Jan Kulawik, Dorota Szwagierczak and Agata Skwarek

The purpose of this study was to develop fabrication procedure of multilayer varistors based on doped ZnO and to investigate their microstructure and electrical properties.

Abstract

Purpose

The purpose of this study was to develop fabrication procedure of multilayer varistors based on doped ZnO and to investigate their microstructure and electrical properties.

Design/methodology/approach

Two ceramic compositions based on ZnO doped with Bi2O3, Sb2O3, CoO, MnO, Cr2O3, B2O3, SiO2 and Pr2O3 were used for tape casting of varistor tapes. Multilayer varistors were prepared by stacking of several green sheets with screen printed Pt electrodes, isostatic lamination and firing at 1,050-1,100°C. Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) studies were carried out to examine the microstructure and elemental composition of the varistors. Current-voltage characteristics were measured in the temperature range from −20 to 100°C.

Findings

The desired compact and fine-grained microstructure of multilayer varistors and nonlinear current-voltage characteristics were attained as a result of the applied fabrication procedure. The breakdown voltage of the varistors is 33-35 V and decreases slightly in the temperature range from −20 to 100°C. The nonlinearity coefficient changes from 14 to 23 with rising measurement temperature.

Originality/value

New improved formulations of varistor ceramic foils based on doped ZnO were developed using tape casting method and applied for fabrication of multilayer varistors with good electrical characteristics. The influence of temperature in the range from −20 to 100°C on the varistor parameters was studied.

Details

Microelectronics International, vol. 34 no. 3
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 5 October 2012

M. Simon and E.L. Meyer

The purpose of this paper is to design and construct a low‐cost current‐voltage tester, bearing in mind the short falls of the existing testers and the ever‐increasing…

Abstract

Purpose

The purpose of this paper is to design and construct a low‐cost current‐voltage tester, bearing in mind the short falls of the existing testers and the ever‐increasing price of the testers currently on the market. The I‐V tracer presented in this paper uses a variable external power supply unit (PSU) as the load, in order to obtain the entire operating range of a PV module from open circuit through maximum power to short circuit condition.

Design/methodology/approach

The I‐V tracer presented in this paper was divided into three main sections, mainly the data acquisition system (DAS), which comprises an A/D computer card, temperature card, electromechanical relays, current and voltage transducers, aluminum housed resistors and power MOSFETS, the variable load (programmable variable PSU) and finally the signal processing unit. These components were integrated and finally interfaced to a PC.

Findings

The results obtained using this system compared with the capacitive tester show a low percentage difference of <1 from the comparative I‐V curves measured. The results measured by the PSU tester are also of high accuracy. The findings also demonstrated the fact that most of the components found in most university laboratories can be used to build the PSU tester and still obtain highly accurate results.

Research limitations/implications

Since some components are semiconductors, which have a limited lifetime, they need to be changed if they fail. Mostly the MOSFETS should be replaced when no switching signal is sent.

Practical implications

This low‐cost PSU tester is suitable for researchers in disadvantaged institutions whose research capabilities are limited due to the high cost of this equipment.

Originality/value

The PSU tester uses a variable power supply as the load to measure PV module I‐V curves. The system is capable of measuring up to eight modules at the same time, making it possible to analyze PV modules within the same time frame.

Details

Journal of Engineering, Design and Technology, vol. 10 no. 3
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 11 May 2010

Asmiet Ramizy, Wisam J. Aziz, Z. Hassan, Khalid Omar and K. Ibrahim

The purpose of this paper is to describe how fabricate solar cell based‐on porous silicon (PS) prepared by electrochemical etching process is fabricated and the effect of…

Abstract

Purpose

The purpose of this paper is to describe how fabricate solar cell based‐on porous silicon (PS) prepared by electrochemical etching process is fabricated and the effect of porosity layer on the solar cell performance is investigated.

Design/methodology/approach

The techniques used include SiO2 thermal oxidation, ZnO/TiO2 sputtering deposition and PS prepared by electrochemical etching. Surface morphology and structural properties of porous Si were characterized by using scanning electron microscopy. Photoluminescence and Raman spectroscopy measurements were also performed at room temperature. Current‐voltage measurements of the fabricated solar cell were taken under 80 mW/cm2 illumination conditions. Optical reflectance was obtained by using optical reflectometer (Filmetrics‐F20).

Findings

Pore diameter and microstructure are dependent on anodization condition such as HF: ethanol concentration, duration time, temperature, and current density. On other hand, a much more homogeneous and uniform distribution of pores is obtained when compared with other wafer prepared with different electrolyte composition.

Originality/value

PS is found to be an excellent anti‐reflection coating against incident light when it is compared with another anti‐reflection coating and exhibits good light‐trapping of a wide wavelength spectrum which produce high efficiency solar cells (11.23 per cent).

Details

Microelectronics International, vol. 27 no. 2
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 20 June 2019

Barbara Swatowska, Piotr Panek, Dagmara Michoń and Aleksandra Drygała

The purpose of this study was the comparison and analysis of the electrical parameters of two kinds of silicon solar cells (mono- and multicrystalline) of different…

Abstract

Purpose

The purpose of this study was the comparison and analysis of the electrical parameters of two kinds of silicon solar cells (mono- and multicrystalline) of different emitter resistance.

Design/methodology/approach

By controlling of diffusion parameters, silicon mono- (Cz-Si) and multicrystalline (mc-Si) solar cells with different emitter resistance values were produced – 22 and 48 Ω/□. On the basis of current-voltage measurements of cells and contact resistance mapping, the properties of final solar cells based on two different materials were compared. Additionally, the influence of temperature on PV cells efficiency and open circuit voltage (Uoc) were investigated. The PC1D simulation was useful to determine spectral dependence of external quantum efficiency of solar cells with different emitter resistance. The silicon solar cells of 25 cm2 area and 240 µm thickness were investigated.

Findings

Considering the all stages of cell technology, the best structure is silicon solar cell with sheet resistance (Rsheet) of 45-48 Ω/□. Producing of an emitter with this resistance allowed to obtain cells with a fill factor between 0.725 and 0.758, Uoc between 585 and 612 mV, short circuit current (Isc) between 724 and 820 mA.

Originality/value

Measurements and analysis confirmed that mono- and multicrystalline silicon solar cells with 48 Ω/□ emitter resistance have better parameters than cells with Rsheet of 22 Ω/□. The contact resistance is the highest for mc-Si with Rsheet of 48 Ω/□ and reaches the value 3.8 Ωcm.

Details

Microelectronics International, vol. 36 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

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Article
Publication date: 1 May 2019

Wenjing Li, Qi Wang, Yongshan Ma, Tianyi Jiang, Yanyan Zhu, Yuanyuan Shao, Cuizhen Sun and Junsen Wu

Self-organization has been regarded as a tool for the synthesis of well-defined organic nanostructures. Heterocyclic annulated perylene diimides are the subjects of…

Abstract

Purpose

Self-organization has been regarded as a tool for the synthesis of well-defined organic nanostructures. Heterocyclic annulated perylene diimides are the subjects of considerable current research studies. The purpose of this study is to reveal the photophysical property, electronic structure and solid-state packing of O-heterocyclic annulated perylene diimide.

Design/methodology/approach

Asymmetrically five-membered O-heterocyclic annulated perylene diimide (OAPDI) was synthesized. Structure and purity of OAPDI were confirmed by 1H NMR, 13C NMR, IR and mass spectral techniques. Photophysical properties of OAPDI were studied using UV–vis absorption and fluorescence in both solution (CHCl3) and solid state. Scanning electron microscopic and atomic force microscopy were used to characterize the surface morphology of OAPDI. Conducting properties of the OAPDI were evaluated by current–voltage measurements. The compounds geometries were also optimized at 6-31G* using density functional theory.

Findings

The UV–vis absorption and fluorescence spectra of OAPDI in solution are blue-shifted in comparison with that of unsubstituted perylene bisimide. Solid-state UV–vis measurements of OAPDI indicate that it is capable of forming highly ordered structure. The non-covalent interactions, electrostatic attraction and p-p stacking moieties of OAPDI synergistically guide assembly and domain growth while maintaining the interpenetrating network of nanofibers in the solid film. The OAPDI gave higher current at −2.0 V (0.68 µA) and 4.0 V (1.0 µA).

Originality/value

This study will be helpful for exploring feasible routes to acquire soluble perylene diimides and well-defined organic nanostructures. Furthermore, such molecular tailoring approach would be helpful for designing and synthesizing novel organic semiconductive materials with excellent charge-transporting and light-emitting capabilities.

Details

Pigment & Resin Technology, vol. 48 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 5 March 2020

Piotr Firek, Jakub Szarafiński, Grzegorz Głuszko and Jan Szmidt

The purpose of this study is to directly measure and determine the Si/SiO2/AlOxNy interface state density on metal insulator semiconductor field effect transistor (MISFET…

Abstract

Purpose

The purpose of this study is to directly measure and determine the Si/SiO2/AlOxNy interface state density on metal insulator semiconductor field effect transistor (MISFET) structures. The primary advantage of using aluminum oxynitride (AlOxNy) is the perfectly controlled variability of the properties of these layers depending on their stoichiometry, which can be easily controlled by the parameters of the magnetron sputtering process. Therefore, a continuous spectrum of properties can be achieved from the specific values for oxide to the specific ones for nitride, thus opening a wide range of applications in high power, high temperature and high frequency electronics, optics and sensors and even acoustic devices.

Design/methodology/approach

The basic subject of this study is n-channel transistors manufactured using silicon with 50-nm-thick AlOxNy films deposited on a silicon dioxide buffer layer via magnetron sputtering in which the gate dielectric was etched with wet solutions and/or dry plasma mixtures. Furthermore, the output, transfer and charge pumping (CP) characteristics were measured and compared for all modifications of the etching process.

Findings

An electrical measurement of MISFETs with AlOxNy gate dielectrics was conducted to plot the current-voltage and CP characteristics and examine the influence of the etching method on MISFET parameters.

Originality/value

In this report, a flat band and threshold voltage and the density of interface traps were determined to evaluate and improve an AlOxNy-based MISFET performance toward highly sensitive field effect transistors for hydrogen detection by applying a Pd-based nanocrystalline layer. The sensitivity of the detectors was highly correlated with the quality of the etching process of the gate dielectrics.

Details

Microelectronics International, vol. 37 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

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