Tomas Wagner

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• Professor
• Head of Department at University of Pardubice

A systematic study of the doping ability of the TeO2–ZnO–BaO glassy system with Er³⁺ ions is presented to achieve strong Stokes/upconversion photoluminescence (UPL) emission and to determine the optimal experimental conditions for conducting Judd–Ofelt (JO) analysis in Er-doped materials using the newly introduced Combinatorial JO analysis in this...

The superionic phase can be different from the usual phase when we characterize the dynamic and collective effects in condensed matter. One of the lithium superionic conductors, Li10GeP2S12, exhibits the highest ionic conductivity (~ 10–2 S cm⁻¹ at room temperature). Dynamic properties of ac transport (electrochemical impedance spectroscopy) in Li1...

Combinatorial analysis was introduced and employed to calculate JO parameters using all observed absorption bands and their mutual combinations. The presented results then enable the identification of critical absorption band combinations necessary for accurate Judd-Ofelt analysis in Er3+-doped materials, ensuring consistent and reliable outcomes....

Short range order and topology of Ge$_x$S$_{100-x}$ glasses over a broad composition range (20 $\le$ x $\le$ 42 in at%) was investigated by neutron diffraction, X-ray diffraction, and Ge K-edge extended X-ray absorption fine structure (EXAFS) measurements. The experimental data sets were fitted simultaneously in the framework of the reverse Monte C...

The single-phase Ho³⁺-doped Yb3Ga5O12 garnet nanocrystals were synthesized by the sol-gel combustion technique using citric acid. Their structure, morphology and chemical composition were examined by the powder X-ray diffraction, attenuated total reflectance-Fourier transform infrared spectroscopy and Energy-dispersive X-ray spectrometry with the s...

The structural properties of two Ge-As-Se glass compositions (Ge10As10Se80 and Ge21As21Se58) are investigated from a combination of density-functional-based molecular dynamics simulations and neutron/x-ray scattering experiments. We first focus on structural characteristics, including structure factors, pair distribution functions, angular distribu...

Lattice mismatched heterointerfaces are classified by a simple five parameter configuration space which allows to quantify the following properties: gradual partial coherence, distribution and localisation of misfit dislocations, anisotropy of strain fields, elastic dissimilarity of the lattices. HREM images are digitally processed into one-dimensi...

Fulltext can be downloaded for free using: https://authors.elsevier.com/a/1eZNZ54fBDeYS --- We report the thorough study on glass forming ability and properties of the TeO2 - ZnO-BaO (TZB) optical glasses prepared by the melt-quenching method at 900 °C. The attention has been paid to investigation of thermal, structural, and optical properties of g...

The nanocrystalline single‐phase Er³⁺‐doped Yb3Ga5O12 garnets have been prepared by the sol‐gel combustion technique with a crystallite size of ≈30 nm. The presence of Yb³⁺ in garnet hosts allows their efficient excitation at the ≈977 nm wavelength. The Er³⁺ doping of Yb3Ga5O12 garnet host results in deep red Er³⁺: ⁴F9/2 → ⁴I15/2 upconversion photo...

The year 2021 is the year of the 85th anniversary of the birth of Professor Miloslav Frumar the enthusiastic chemist who dedicated his whole professional life to the study of amorphous and glassy chalcogenides which are used in numerous applications like copying machines, laser printers, DVDs or memories.

Mass spectra of (GeS2)50(Sb2S3)50 glass and Ag-doped glasses [5% Ag (GeS2)50(Sb2S3)50 and 15% Ag (GeS2)50(Sb2S3)50] obtained using laser desorption ionization (LDI) time-of-flight coupled with quadrupole ion trap mass spectrometry were studied. The analysis of the mass spectra indicated the formation of Ag a Ge b Sb c S d clusters. In addition...

Herein, in situ temperature‐dependent THz and DC conductivity measurements in the crystalline states of Ge2Sb2Te5 (GST225) are performed at relatively high temperatures (>300 K). As observed in many nanomaterials, a non‐Drude type of THz conductivity is found in the crystalline state of phase‐change (PC) materials. Both the intra‐ and intergrain ef...

2D metallic material is an important group member in 2D material family. Many applications have been applied in the catalysis and devices. In this paper, we present a novel method to prepare the tungsten 2D material, which is simple and powerful. The W thin film is deposited via magnetron sputtering. As-deposited tungsten thin film is able to be ex...

In this study, a universal Ge2Sb2Te5 phase change material was sputtered to obtain a layered structure. The crystalline phase of this material was prepared by annealing. SEM (scanning electron microscopy) and HRTEM (high-resolution transmission electron microscopy) images give confirmed that the sputtered Ge2Sb2Te5 thin film in crystalline phase ha...

Microstructure of (GeS3)100-xAgx (x = 0, 5, 10, 15, 20, 25) and (GeS2)100-xAgx (x = 0, 5, 10, 15, 20) has been studied by scanning electron microscopy. It is found that the glasses of both systems are phase separated: (GeS3)100-xAgx for 5 ≤ x ≤ 20 at.% and (GeS2)100-xAgx for 10 ≤ x ≤ 15 at.%. Morphology of coexisting phases is essentially dependent...

In this paper, GeSe 2 thin film and glass ingot were prepared in a layered structure. Subsequently, the 2D amorphous monolayers were achieved from layered thin film and layered glass ingot. The thicknesses of monolayers from thin film range from 1.5 nm to 5 nm. And the thickness of monolayer from glass ingot is 7 μm. The fast cooling of material re...

Tunable and ultrabroadband mid-infrared (MIR) emissions in the range of 2.5–4.5 μm are firstly reported from Co²⁺-doped nano-chalcogenide (ChG) glass composites. The composites embedded with a variety of binary (ZnS, CdS, ZnSe) and ternary (ZnCdS, ZnSSe) ChG nanocrystals (NCs) can be readily obtained by a simple one-step thermal annealing method. T...

The paper reports on ≈1.5 μm Stokes photoluminescence (PL) emission and upconversion photoluminescence (UCPL) emission in the visible and near-infrared spectral region in Er ³⁺ -doped Ge 25 Ga 8 As 2 S 65 chalcogenide glasses at pumping wavelengths of 980 and 1550 nm. The ≈1.5 μm PL emission spectra are broadened with increasing concentration of Er...

We report, for the first time to our knowledge, an ultrabroadband mid-infrared (MIR) emission in the range of 1800–2800 nm at room temperature from a Cr ²⁺ -doped chalcogenide glass ceramic embedded with pure hexagonal (wurtzite) β-ZnS nanorods and study the emission-dependent properties on the doping concentration of Cr ²⁺ . A new family of chalco...

The AgGeSe2 solid state electrolyte has been studied in resistive switching. According to the I–V relationship, the possible mechanisms, including the SCLC (space-charge-limited current) model is applied to explain the result of experiments. The conductive filament formation is found to be related to the Schottky barrier between the electrode and e...

Impedance spectroscopy is a valuable tool for the analysis of the ionic conductivity of both solid and liquid state materials. Chalcogenide glasses are well known for their high ionic conductivity nature and wide compositional flexibility. As the GeSbSe material has high glass forming ability, it is expected that the materials can be doped with a h...

The distribution of Tm³⁺ and Ni²⁺ ions is unambiguously exhibited in 80GeS2-20Ga2S3 chalcogenide glass ceramics (GCs) containing Ga2S3 nanocrystals (NCs) by using advanced analytical transmission electron microscopy. Distinctively different distribution patterns of Tm³⁺ and Ni²⁺ ions are observed in the GCs obtained by controlled crystallization. T...

In the present article, the silver diffusion behavior and its influence on ionic conduction have been studied from a series of glass samples Agx(Ge16Sb12Se72)100-x with 0 ≤ x ≤ 25. A non-linear evolution of the ionic conduction as a function of Ag concentration was found and attributed to a variation in the diffusion mechanism following the Ag rate...

The presented study shows how the incorporation of silver changes the structure and physical properties of chalcogenide glass (GeS2)50(Sb2S3)50. Nine samples with silver content (0–25 at. %) were studied to give a detailed picture. The structure and its changes were analyzed by Raman spectroscopy. The medium range order of the (GeS2)50(Sb2S3)50 gla...

Herein, the synthesis of BiOCl nanoplatelets of various dimensions is demonstrated. These materials were prepared by anodic oxidation of Bi ingots in diluted HCl under dielectric breakdown conditions, triggered by a sufficiently high anodic field. Additionally, it is shown that the use of several other common diluted acids (HNO3, H2SO4, lactic acid...

A new type of memory device, based on Ag and Cu doped Ge2Se3 chalcogenide, was designed and investigated by a new method, referred to as “one pulse SET method”. The device shows multilevel resistance states. A resistance state between ON and OFF states was found with a wide range of bias. The multilevel resistance behavior could be caused by the fo...

We report on the Er³⁺ ↔ Ho³⁺ optical interaction on the 1.2 and 1.5 µm near-infrared and visible upconversion photoluminescence in Er³⁺/Ho³⁺-co-doped GeGaS glasses at pumping wavelength of 980 nm. Since the 980 nm pumping wavelength is off resonance for Ho³⁺ intra-4f electronic transitions, we have utilized the Er³⁺ sensitization with observed effi...

The complex dielectric function, the Er3+ Stokes emission at ≈1540 nm and the upconversion photoluminescence at ≈990 nm of pulsed-laser deposited thin-film GeGaSbS:Er3+ are studied. The linear-refractive-index dispersion is obtained by fitting spectroscopic ellipsometry data to the Sellmeier and the Cody-Lorentz parametrizations. The former model i...

Selective doping of optically active ions into the nanocrystalline phase(s) of glass ceramics is of interest for photoluminescence (PL) applications to control the energy transfer (ET) processes between dopants on the nanometer length scale. Here, the focus is on explaining the essential knowledge of the distribution of two groups of active ions: t...

The amorphous structure of (Ga2Se3)0.25(GeSe2)0.75 is investigated using a combination of anomalous X-ray scattering (AXS) and Reverse-Monte-Carlo (RMC) modeling. It was confirmed that the Ga and Ge atoms can be found exclusively in the tetrahedral configuration. The average coordination number of the Se atoms is found to be 2.34(3) due to the pres...

Time-resolved Raman measurements reveal a three-stage mechanism of photostructural changes in Ge25.0Ga9.5Sb0.5S65.0 (containing 0.5 at.% of Er3+) glass under continuous-above-bandgap illumination. These changes are reversible and effectively athermal, in that the local temperature rises to about 60% of the glass-transition temperature and the phase...

The time-resolved Raman measurements reveal a three-stage mechanism of the photostructural changes in Ge25.0Ga9.5Sb0.5S65.0 (containing 0.5 at. % of Er3+) glass under continuous-above-bandgap illumination. These changes are reversible and effectively athermal, in that the local temperature rises to about 60% of the glass-transition temperature and...

In this work the structure, thermal, electrical and optical properties of Ge8Sb2-xBixTe11 (x = 0; 1; 2) thin films were investigated. Thin films were prepared by Flash Thermal Evaporation (FE) and by Pulsed Laser Deposition (PLD) techniques. The amorphous structure of all as-deposited films were proofed by X-ray diffraction analysis. All samples cr...

Silver indium diselenide quantum dots were successively synthesized by colloidal sol-gel method by chelating with organic ligand oleylamine (OLA). The particle size was studied by transmission electron microscopy (TEM) and the size was found about 10 nm. X-ray diffraction (XRD) was used to study crystalline structure of the nanocrystals. The grain...

The resistive random access memory is promising to replace the traditional memory technology and the buffer layer plays an important role in chalcogenide based electrolytes. However, there is still lack of convincing experimental result regarding with the mechanism of buffer layer. In this letter, two sets of devices were designed with different po...

We report on the optical properties of the Er-doped As3S7 chalcogenide films prepared by the two step dissolution process utilizing the As3S7 glass dissolved with propylamine and further addition of tris(8-hydroxyquinolinato)erbium(III) (ErQ) complex acting as Er³⁺ precursor. Thin films were deposited by spin-coating, thermally stabilized by anneal...

Zinc sulphide (ZnS) and Cu-doped ZnS nanoparticles were synthesized by the wet chemical method. The nanoparticles were characterized by UV-Visible, Fluorescence, Fourier Transform Infra-red Spectrometry (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectrometry (XPS), field emission scanning electron microscopy (FESEM), and high resolution t...

The article presents the formulas of quadrature frequency resolved spectroscopy (QFRS) on the upconversion photoluminescence (UCPL) of rare-earth (RE) doped materials on the general M-level model. The formulas are derived in matrix-equation form with the first-order perturbation on the rate equations at the M energy-levels of RE ion. The QFRS spect...

Atom-probe tomography of Ag-photodoped amorphous thin-film Ge40S60, the material of interest in nano-ionic memory and lateral geometry MEMS technologies, reveals regions with two distinct compositions on a nanometer length-scale. One type of region is Ag-rich and of a size typically extending beyond the measured sample volume of ~40x40x80 nm3. Thes...

The paper addresses the quadrature frequency resolved spectroscopy (QFRS) on the red (⁴F9/2 → ⁴I15/2) upconverted photoluminescence (UCPL) as well as the green (⁴S3/2 → ⁴I15/2) UCPL of Er³⁺ in GeGaS chalcogenide glasses at the pump wavelength 975 nm. On the basis of the perturbed rate equations for the generally accepted 5-level model of the green...

2017, The Author(s). Atom-probe tomography of Ag-photodoped amorphous thin-film Ge 40 S 60 , the material of interest in nano-ionic memory and lateral geometry MEMS technologies, reveals regions with two distinct compositions on a nanometer length-scale. One type of region is Ag-rich and of a size typically extending beyond the measured sample volu...

We report on the photovoltaic performance of novel T-Shaped Indan-1,3-dione derivatives as donors in a solution processed bulk heterojunction solar cells. Small molecule bulk heterojunction solar cells of these molecules with [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) were fabricated and characterized. The preliminary characterization of t...

We investigated the physicochemicаl properties, structure and optical properties of the Ge25Ga9.5Sb0.5S65: Er³⁺/Yb³⁺ glasses. The Judd-Ofelt theory was used to calculate the intensities of the intra-4f electronic transitions of Er³⁺ ions. We observed the upconversion photoluminescence (UCPL) at 530, 550, 660 and 810 nm under 980 nm excitation. In t...

Here we report first time the direct observation of the nucleation and growth process of CdS nanowires by stirring of CdS nanoparticles. The growth process of CdS nanowires consist of three steps, the growth of CdS particles, nucleation of CdS nanorods and finally the growth of CdS nanowires. This method brings forward a new idea to synthesize nano...

Here we report on a Li-S battery with cathode, based on a S powder obtained from bulk amorphous S, by cryogenic grinding. The cathode was prepared from a slurry, wherein the content of cryo-ground S powder was equal to 80 wt % (corresponds to ≈ 2.26 mg cm⁻²). Other slurry components included carbon Super P, and polyvinylidene fluoride, dispersed in...

The effect of Ag-doping on the thermokinetic behavior (cold crystallization and structural relaxation kinetics, glass-forming ability) of the Agy[(GeS2)50(Sb2S3)50](100 − y) glasses was studied by using differential scanning calorimetry, Raman spectroscopy and X-ray analysis – compositions up to y = 25 were included in the study. Structural relaxat...

Although the persistent photocurrent or the residual photocurrent decay (RPD) in photoconductive semiconductors is known to be dominated by dispersive recombination kinetics which produce the stretched exponential functional decay, exp(-Ctβ), where β (<1.0) is the dispersion parameter, the reason for the occurrence of the RPD is still not clear. We...

Electrochemical metallization cells (EMC) are based on the electrochemical growth and removal of nanoscale metallic filaments in thin films of solid elektrolyte. EMC shows a great promise to replace conventional data storage technologies. It has low programming current and voltage and smaller sizes that can be seen as a way to store more data in sm...

In this paper, a study of resistive switching in AgxAsS2 layer, based on a utilization of conductive atomic force microscope (AFM), is reported. As the result of biasing, two distinct regions were created on the surface (the conductive region and non-conductive region). Both were analysed from the spread current maps. The volume change, correspondi...

RationaleThe structure of AgAsS2 glass, which has a broad range of applications, is still not well understood and a systematic mass spectrometric analysis of AgAsS2 glass is currently not available. Elucidation of the structure should help in the development of this material. Methods The AgAsS2 glass was prepared by the melt-quenched technique. Las...

A study of Ag filament formation in resistive switching was carried out by pin probe contact on the surface of Ag doped AsS2. New switching algorithm, consisting of two different voltage steps, in parallel with the classical cyclic voltammetry was explored. The resulting Ag deposition on the AsS2 surface was observed by optical microscopy and scann...

Amorphous and glassy chalcogenides (AGCs) are noncrystalline compounds and alloys with optical transparency and intense luminescence in the infrared region. This review chapter introduces the composition, structure, and fabrication methods of bulk and thin film AGCs. Their physical and chemical properties and applications in different fields have a...

Density functional/molecular dynamics simulations have been performed to determine structural and other properties of amorphous Ag/Ge/S and Ge/S alloys. In the former, the calculations have been combined with experimental data (x-ray and neutron diffraction, extended x-ray absorption fine structure). Ag/Ge/As alloys have high ionic conductivity and...

Quadrature frequency resolved spectroscopy (QFRS) on green (~550 nm) upconversion photoluminescence (UCPL) of Ge–Ga–S: Er3+ glasses pumped at 975 nm revealed double-peaked spectra with long lifetime τ 1 ranging from 0.2 to 2 ms and short lifetime τ 2 ≈ several tens of μs. The results are analysed in terms of the transfer function derived by lineari...

Although a proposal of resonance bonds in crystalline phase-change materials based on the GeSbTe system has been provided, we do not find any clear evidence in favor of the proposal. The ellipsometric study demonstrates that a change in the high frequency dielectric constant ε∞ between the amorphous and crystalline phases is only scaled by the aver...

For the first time Inverted ternary bulk hetrojunction hybrid photovoltaic device based on AgInSe2 – polymer blend as absorber and PEDOT:PSS as hole transport layer was fabricated and characterized. Blends of MDMOPVV.PCBM.AIS (MDMOPVV-Poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene], PCBM-(Phenyl-C61-butyric acid methyl ester), AIS-...

Synthesis and applications of organotin(II) sulfide ({2,6-(Me2NCH2)2C6H3}Sn)2(μ-S) (1), organotin(II) thiophenolate {2,6-(Me2NCH2)2C6H3}Sn(SPh) (2) and organotin(IV) heptasulfide {2,6-(Me2NCH2)2C6H3}2Sn2S7 (3) as potential single-source precursors (SSPs) for the deposition of SnS or SnS2thin films using a spin-coating method are reported. Compounds...

The paper reviews and discusses crystalline, nanocrystalline, glassy and amorphous chalcogenides and their thin films and fibres, their preparation, structure, properties, changes and applications in optics, optoelectronics and electronics, data storage and sensors with accent on recent data and progress. The area of interest is so broad that only...

The current work consists of nine contributions describing recent progress in the interdisciplinary of Nanoscience, which involves physics, chemistry, engineering, biology and medicine and one essay outlining some important historical and socioeconomic factors pertaining to recent developments in nanoscale science and technology. All 10 chapters ha...

The chapter describes details of deposition techniques, namely thermal evaporation, sputtering, pulsed-laser deposition, chemical vapour deposition and spin-coating for chalcogenide thin films. We discuss key issues, advantages and influence of different deposition techniques and experimental conditions on properties of as-prepared amorphous chalco...

This chapter covers state of the art in physical ageing of chalcogenide glasses. The thermodynamic origin of this phenomenon, experimental possibilities for its investigation, up-to-date results, general phenomenology and observed regularities are critically reviewed. The influence of various external factors, such as elevated temperatures, light e...

Electrical properties of a set of lithium-ion conducting sulfide glasses with general formula 20LiI-x Ga 2 S 3 -(80-x)GeS 2 (x = 10, 15 and 20) is studied in the present article. The experimental data obtained using impedance spectroscopy are analyzed by means of a random-walk (RW) model assuming that the conduction takes place by a random motion o...

The need of energy is most discussed issue these days and among various renewable energy sources, solar energy is most reliable one. Collection of solar energy and then conversion to electricity requires semiconducting materials. After inorganic junctions, Organic materials have got a pretty attention because of many advantages of them. In this rev...

We present a microscopic model, describing the THz conductivity of semiconductors with nanosized grains. The model combines free intra-grain motion and hopping on grain boundaries, and it is verified by fitting experimental spectra of phase-change materials and extracting the underlying parameters.

The bulk samples of SbxSe100 − x system (x=90, 85, 80) and their amorphous thin films were prepared by flash evaporation method. The films possess good thermal stability and high values of the activation energy of crystallization. The activation energy of crystallization (Ea) of the thin films Sb85Se15 and Sb80Se20 was found to be 2.97 and 2.55 eV,...

In the present work, we report the structural and optical properties of sol-gel synthesized Zn0.9(Cd1-xMgx)0.1O (0 ≤ x ≤ 1.0) nanostructured films investigated by using the X-ray diffraction, scanning electron microscopy, atomic force microscopy, electrical resistivity, optical absorption and photoluminescence spectroscopic techniques. The X-ray d...

Blends of MdPVV.PCBM.AIS were investigated for Photovoltaic applications. AgInSe2 powder was synthesized by sealing and heating the stoichiometric constituents in evacuated quartz tube ampule. Fine grinded AIS powder was dispersed in MD-MOPVV and PCBM with and without surfactant. Different concentrations of these particles were suspended in the pol...

The objective of this work was to quantitatively characterize the 3D complexity of ZnO:TiO2 - organic blended solar cells layers by atomic force microscopy and fractal analysis. ZnO:TiO2 - organic blended solar cells layers were investigated by AFM in tapping-mode™ in air, on square areas of 25 μm2. A detailed methodology for ZnO:TiO2 - organic ble...

A quantum dot (QD) solar cell is an emerging field in solar cell research that uses QDs as the photovoltaic material. QDs have band gaps that are tunable across a wide range of energy levels by changing the QD size. Embedding different sized dots within the absorbing layer encourages harnessing the maximum spectrum energy. Also, other effects like...

The versatility of hot embossing for shaping photonic components on-chip for mid-infrared (IR) integrated optics, using a hard mold, is demonstrated. Hot embossing via fiber-on-glass (FOG), thermally evaporated films, and radio frequency (RF)-sputtered films on glass are described. Mixed approaches of combined plasma etching and hot embossing incre...

This paper applies multifractal spectrum theory to characterize the structural complexity of 3D surface roughness of copper (II) tetrasulfophthalocyanine (CuTsPc) films on the indium tin oxide (ITO) substrate, obtained with atomic force microscopy (AFM) analysis. CuTsPc films were prepared by drop cast method on ITO substrate. CuTsPc films surface...

Although the structure of atomic switch Ge2 Sb2 Te5 (GST) thin films is well established, the composition of the clusters formed in the plasma plume during pulsed-laser deposition (PLD) is not known. Laser Desorption Ionization Time-of-Flight Mass Spectrometry (LDI-TOF MS) is an effective method for the generation and study of clusters formed by la...

The dependence of impedance spectra on temperature and sample thickness are analyzed for AgAsS2 as a case example. Using the scaling properties of complex conductivity with thickness and temperature, we discuss the bulk and interfacial properties of the materials. Important physical parameters such as the number of mobile ions, diffusion coefficien...

For an attempt of AIS quantum dots (QDs), AIS nanoparticles with tetragonally distorted phase have been prepared by mechanically alloying the synthesized bulk AIS powder at room temperature in a planetary ball mill under Ar. Nanoparticles are formed with range -10 nm in size. These ball-milled nanoparticles contain different shapes, and the Rietvel...

We report on the new data mining approach based on Random walk theory. Through the full analysis of complex impedance spectra including electrode polarization effect, we derived the number of moving ions and the diffusion coefficient. These useful numbers were extracted without using an equivalent electric circuit. Our approach has the potential to...

Density functional/molecular dynamics simulations and experimental data (x-ray and neutron diffraction, extended x-ray absorption fine structure) have been combined to determine structural and other properties of amorphous AsS2 and AgAsS2. These semiconductors represent the two small regions of the Ag-As-S ternary diagram where homogeneous glasses...

The article discusses the dynamics of photoinduced defect creations (PDC) in amorphous chalcogenides, which is described by the stretched exponential function (SEF), while the well known photodarkening (PD) and photoinduced volume expansion (PVE) are governed only by the exponential function. It is shown that the exponential distribution of the the...

Efficiency enhancement of a multicrystalline silicon solar cell using down-conversion of Tm3+ and Yb3+ doped silicate glasses was investigated. Na2O-CaO-SiO2 glasses doped with Tm3+ or Tm3+ and Yb3+ were prepared. Distributed Bragg Reflector (DBR) coatings were sputtered on the glass surface to control the transmission and reflection of the desired...

THz and DC losses in crystalline states of GeSbTe and AgInSbTe phase-change material systems are re-examined and discussed. Although a simple free carrier transport has been assumed so far in the GeSbTe (GST) system, it is shown through recent experimental results that a series sequence of intragrain and intergrain (tunneling) transport, as recentl...

An advanced approach for resistive switching memory cells based on porous anodic alumina (Al2O3) membranes is reported. The effective resistive switching resulting in 6 orders of magnitude difference in resistivity between “on” and “off” states of the cell is achieved by specific electronic and ionic interaction between Ag nanowires filled in the m...

Photostructural changes—the hallmark of non-crystalline chalcogenides—are in essence the basis of a number of photoinduced effects, i.e., changes of their physical properties, which are exploited in a variety of applications, especially in photonics and optoelectronics. Despite the vast number of investigations of photostructural changes, there is...

This paper presents a multifractal approach to characterize the structural complexity of 3D surface roughness of CuTsPc films on the glass and quartz substrate, obtained with atomic force microscopy (AFM) analysis. CuTsPc films prepared by drop cast method were investigated. CuTsPc films surface roughness was studied by AFM in tapping-mode™, in an...

The structure of Ag-doped GeS3 glasses (0, 15, 20, 25 at.% Ag) was investigated by diffraction techniques and extended x-ray absorption fine structure measurements. Structural models were obtained by fitting the experimental datasets simultaneously by the reverse Monte Carlo simulation technique. It is observed that Ge has mostly S neighbours in Ge...

Online available: http://iafastro.directory/iac/paper/id/18343/summary/ --------------Nowadays, the renewable energy sources are in the forefront of interest including the silicon solar cells. However, the conversion efficiency of P-N junction-based solar cells is limited by Shockley-Queisser limit. This disadvantage can be overcome, e.g. by using...