Ioannis Samaras

Ioannis Samaras
Aristotle University of Thessaloniki | AUTH · School of Physics

phd
Electrical and Electrochemical measurements.

About

49
Publications
213,543
Reads
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627
Citations
Additional affiliations
January 1992 - December 2015
Aristotle University of Thessaloniki
Position
  • PhD
June 1985 - August 1987
Sorbonne Université
Position
  • PhD Student
Education
September 1980 - September 1982
Aristotle University of Thessaloniki
Field of study
  • (master in) Radioelectronics
September 1975 - September 1980

Publications

Publications (49)
Poster
Full-text available
The electrical measurements are based on two new experimental observations. One is the valuable information retrieved from the measured non-zero phase φ between voltage V and current i that registers in complex impedance Z (=V/i). The other is the DC voltage VDC background polarization used for DC power supply ensuring a constant temperature profil...
Conference Paper
Full-text available
Abstract Incandescent light bulbs, apart the common visual illumination, are, also, very useful, from the context of basic (and teaching of basic) physics towards a wider context of engineering, multi-physics and chemistry, as well as, many other, 'application driven', applications. Here, the electrical metrology in incandescent lamps' W-wires is r...
Conference Paper
Full-text available
Tungsten wires in incandescent lamps are one of the oldest bulk nanomachined metals in nanotechnology. Using severe plastic deformation (SPD) techniques, an application driven thermo-mechanical technology of tungsten wires morphology solved many problems of the devices (incandescent lamps). In this work, we investigate the semiconducting properties...
Research
Full-text available
Tungsten wires in incandescent lamps present electrical percolation phenomena due to dielectric K-nanobubbles in a W-metal upon electrical heating, before ligthing. I.Karagiannis, I.Samaras, 30th Panhellenic Conference on SSP & mat.Sci., Heraklion/Crete/Greece 21-24 Sep.2014, page 115 (Poster46); Link "http://fsk30.materials.uoc.gr/bookofabstracts...
Article
Full-text available
Electrochemical investigations on lithium insertion in crystalline layered chalcogenide compounds are presented. Systematic and precise studies of the voltage-composition relation were made in single crystals of InSe, In2Se3, MoS2, TiS2 and NiPS3. The stability of the intercalated phases is discussed on bases of electrochemical potential spectrosco...
Article
Full-text available
Thermoelectric generators (TEGs) make use of the Seebeck effect in semiconductors for the direct conversion of heat to electrical energy. The possible use of a device consisting of numerous TEG modules for waste heat recovery from an internal combustion (IC) engine could considerably help worldwide efforts towards energy saving. However, commercial...
Poster
Full-text available
The “excess” light created by incandescent light bulbs may become more efficient if we make-force the NB to adsorb less and emit more by : science : 1. understanding better their properties (nano-science). 2. Consider them as emitting cavities by increasing their nano-size one order. material science : 3. Make the bigger (emitting) cavities (from 5...
Article
Measurements of assembled thermoelectric (TE) modules commonly include investigations of the module output power versus load resistance. Using an AC electrical measurement for TE modules, a model of equivalent passive RC circuit has been developed and tested for both the thermal and electrical characteristics of the module. In this work we present...
Article
Full-text available
In this paper, thin film bi-layers of LiCoO2 cathode material and xLi2O-B2O3 electrolyte glasses were prepared by e-gun evaporation. The ionic conductivity of the electrolyte films was measured by employing impedance spectroscopy technique and the results, for different chemical compositions of the electrolyte, are compared. Auger electron spectros...
Article
Full-text available
Cathode powders of the Li–Mn–Ni–O system have been prepared at a Mn/(Mn+Ni) ratio varying from 0 to 1. The solid state reaction method was used to obtain the cathode materials by mixing MnO2, LiCO3 and NiO. A 20% excess of lithium was used in the precursors. The materials produced were examined by X-rays to identify their structure. Batteries were...
Article
Metallic Li anode present serious problems, so we are applying the concept of an inert matrix to shield a battery anode, proposed by Huggins 15 years ago (Wang et al., 1986); Today, carbon anode based Li-ion polymer electrolyte batteries' technology is enjoying wide commercial success. However certain carbon material forms as well as liquid electro...
Chapter
Full-text available
All solid state lithium secondary batteries are more safe and reliable. By using carbon, SnO2 or Li-Al alloys the problems created by the metallic lithium can be avoided [1]. Tailoring of sp2/sp3 ratio in carbon films is quite controlable today and we can optimize the film properties towards anode electrode for Li-ion microbatteries. So, there is a...
Article
Full-text available
Magnetic properties of a series of Mg-doped granular samples were studied by means of vibrating-sample and SQUID magnetometry. The equilibrium moment measured after the sample demagnetization gave evidence that the surface barrier effects can be neglected up to 60 K. Slope of the high-field dependence was used for determination of the temperature d...
Article
This chapter describes ferroelectrics and their possible involvement in biology. Thales of Miletus (6th century B.C.) made the first observations of electricity by rubbing pieces of amber. Spontaneous charge separation also appears with ferroelectric materials, where at the molecular level the positive charge center is shifted relative to the negat...
Article
Lithiated spinel manganese dioxide was synthesised from electrochemical MnO2 and Li2CO3 with deficiency or excess lithium (LixMn2O4, 0.8<x<1.3) for use in Li/LixMn2O4 and Li-ion cells. Micron-sized Li1.05Mn2O4 prepared at 730°C showed high Li utilization, excellent cyclability and good rate capability with an initial discharge capacity of 123 mA h/...
Article
The off-state current in n - and p -channel polycrystalline silicon thin-film transistors (polysilicon TFTs) is investigated systematically by conduction measurements at various temperatures and low-frequency noise measurements at room temperature. It is demonstrated that the leakage current is controlled by the reverse biased drain junction. The m...
Article
The intercalation process of Li in molybdenum trioxide (MoO3), a layered transition metal oxide that has been proposed as candidate cathode material for rechargeable batteries, is examined in relation to the crystallinity and the growth method of the pristine material. Atomic Force Microscopy (AFM) is used for surface roughness calculations. Roughn...
Article
Single crystals of the layered structure wide band semiconductor MoO3 were grown and Al was intercalated electrochemically. Intercalation was monitored by X-ray microprobe analysis. Optical transmission measurements in the fundamental energy gap region indicate a shift of the absorption edge which is attributed to the intercalated Al species. In th...
Article
Indium selenide films are formed on silica slides and silicon wafers using a flash evaporation technique in which the material source stoichiometry is modified to obtain films with various compositions. The structural and optical properties of indium selenide films are reported. These characterizations have shown that, using different growth condit...
Conference Paper
Full-text available
Rechargeable cells with alkali metal anode and solid solution cathode are considerably promising for high energy density batteries and micro-batteries[1] based on an intercalation reaction. Under appropriate conditions a topochemical reaction of specific particles and a pre-existing structure having a large number of certain energy states may proce...
Article
This work reports a study of the optical and electrical properties of tin monoselenide SnSe and tin dichalcogenides SnX2 with . The semiconducting character of the single crystals is investigated by means of resistivity and Hall effect in the temperature range from 90 to 300 K. The energy gap data are obtained by absorption measurements. The far-in...
Article
We present a study of the transport measurements on lithium intercalated InSe single crystals. Lithium intercalant acts as a donor species and after intercalation the resistivity falls below 0.02 Ω cm with an increase in the carrier density. At low temperature pure InSe exhibits a two-dimensional conductivity owing to weak localization as a consequ...
Article
Full-text available
Optical and electrical-transport measurements carried out on pure and lithium-electro-intercalated TiS2 single crystals are presented. Results for equilibrated samples are shown as a function of temperature and lithium concentration. Resistivity and Hall-coefficient measurements show that upon intercalation there is an increase in the carrier conce...
Article
We have investigated the electrochemical and transport properties of lithium-intercalated NiPS3. Thermodynamic and kinetic results have been obtained by the modified galvanostatic intermittent titration technique for the long-time regime in the compositional range 0 ⩽ x ⩽ 1.5. The chemical diffusion coefficient of lithium in is composition dependen...
Article
Full-text available
Optical and electrical-transport measurements carried out on pure and lithium-electro-intercalated TiS2 single crystals are presented. Results for equilibrated samples are shown as a function of temperature and lithium concentration. Resistivity and Hall-coefficient measurements show that upon intercalation there is an increase in the carrier conce...
Article
In order to explain new peaks in the Raman spectra of MoS2 after intercalation with Li, the lattice dynamics in LixMoS2 is calculated by applying the central force model. It is found that they can be attributed to new vibrational modes in which the intercalant atoms strongly vibrate against the host lattice. The force constants between Li and S ato...
Article
Full-text available
The transport properties and far-infrared reflectivity of BiSI, BiTel, SbTeI, Bi2 Se3 and Bi2S3 have been studied, and the results show a good agreement between the two techniques. Lithium insertion within metal-chalcogen-halogen compounds has been carried out using Li/LiC1O4-PC/MChI galvanic cells at room temperature. Electrochemical potential spe...
Article
The insertion of TlInSe2 chain crystals with lithium ions has been accomplished using an electrochemical method in non-acquous galvanic cells. Electrochemical properties have been studied during the first discharge and optical properties have been investigated on pure and Li-inserted samples by using FTIR spectroscopy. The EMF vs x(Li) in LixTlInSe...
Conference Paper
Full-text available
Insertion process kinetics have been studied by potential sweep voltammetry in InSe and In2Se3 thin films. The influence of the growth conditions of the host material has been determined between the limits of the diffusion with the cell In-Se film/LiClO4-PC/Li. The diffusion coefficient of lithium in thin film is estimated and compared with galvano...
Article
Raman scattering and IR absorption were studied in lithium-intercalated MoS2 at room temperature. After intercalation, new Raman peaks were observed on the low frequency sides of the high-frequency original Raman peaks and around a rigid layer mode. This fact indicates the formation of superlattice structure along the c axis. An intercalation mode...
Article
Results are presented for discharge processes of lithium electrochemical cells containing layered chalcogenide materials. Systematic and precise studies of the voltage-composition relation were made of lithium insertion in InSe, In2Se3, MoS2, TiS2 and NiPS3. The stability of the intercalated phases is discussed on the basis of electrochemical poten...
Article
Full-text available
We report electrochemical investigations of lithium-intercalculated thin films of InSe and In2Se3 obtained by the flash evaporation technique. Studies are conducted for different conditions of preparation and annealing treatment. Results of galvanostatic experiments to measure the thermodynamic and kinetic parameters of the Li/In-Se film cells are...
Article
Defects created by intercalation in MoS2 single crystals were studied by plane and cross-sectional electron microscopy. In the first stage of intercalation the effect is to create extensive dislocations. Further intercalation leads to a structural transformation of the type 2H → 1T, as is evident from the appearance of spots in the diffraction patt...
Article
Full-text available
Indium selenide thin films prepared by flash evaporation were studied as possible cathodes in lithium batteries. Electrical and electrochemical properties are presented for films obtained under different conditions. Intercalation processes have also been investigated using the potential sweep voltammetry and the influence of the host structure has...
Article
The effects of lithium intercalation in In2Se3 have been studied using different methods. Electrochemical properties of the non-stoichiometric LixIn2Se3 phase are given in the range 0 ⩽ × ⩽ 1 for either quenched or annealed compounds. Electronic conductivity has been measured during the insertion process in n-butyl lithium and suggests weak charge...
Conference Paper
Full-text available
Indium selenide films prepared by flash evaporation were studied as possible cathodes in lithium batteries. Electrical and electrochemical properties are presented for films obtained under different conditions. Intercalation processes have also been investigated using the potential sweep voltametry and the influence of the host structure has been o...
Article
In PbTexSe1 − x/PbTe heterojunctions the density of misfit dislocations increases as the mole fraction of selenium increases. If the misfit is small the misfit dislocations are segmented, while for a large misfit they form an interwoven network. The former are mobile during an annealing process and the latter are quite stable since they cannot clim...

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Projects (10)
Project
This project goal is to provide a network for easier and multiple publications and data sharing, increasing this way the response rate and the number of recommendations of authors' work.
Project
Create an interactive environment through new electronic devices and technologies, and the presence of a variety of sources of information and experience. Not to attend the same location through distance learning, and this is one of the most important goals of e-learning. In times of corona virus isolation, the educational process should not "suffer" and we should not lack contacts with students and colleagues.
Project
Review of books of colleagues