Electronic Materials

Red fluorescent emitting monodispersed spherical Y2O3 nanophosphors with different Eu3þ doping concentrations (0–13 mol%) are synthesized by a novel microwave assisted urea precipitation, which is recognized as a green, fast and reproducible synthesis method. The effect of Eu3þ doping and calcination temperature on the structural characteristics and luminescence properties of particles is investigated in detail. The as prepared powders have (Y,Eu)(OH)(CO3) structure which converts to Y2O3:Eu from 500 °C and become crystalline at higher temperatures. The crystallite size of nanophosphors increased from 15 nm to 25 nm as the calcination temperature increased from 700 °C to 1050 °C. The efficient incorporation of Eu3þ ions in cubic Y2O3 host matrix is confirmed by the calculated X-ray Powder diffraction (XRPD) structural parameters. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) micrographs show that the as obtained and calcined particles are spherica...

Materials, The Minerals, Metals & Materials Society (TMS). It incorporates referee's comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is

Nanomaterial-based room temperature gas sensors are used as a screening tool for diagnosing various diseases through breath analysis. The stable planar structure of boron carbide (B 4 C 3 ) is utilized as a base material for adsorption of human breath exhaled VOCs, namely formaldehyde, methanol, acetone, toluene along, with interfering gases of carbon dioxide and water. The adsorption energy, charge density, density of states, energy band gap variation, recovery time, sensitivity, and work function of adsorbed molecules on pristine B 4 C 3 are analyzed by density functional theory. The computed adsorption energies of VOC are in the range of -0.176 to -0.238 eV, and a larger interaction distance validate the physisorption behavior of these VOCs biomarkers on pristine boron carbide monolayer. Minute changes are determined from the electronic band structure of all adsorbed systems conserving the semiconducting nature of the B 4 C 3 monolayer. The band gap variation upon adsorption of VOCs and interfering gases is examined between 0.05 and 0.52%. The 13.63 × 10 -9 s recovery time of methanol is slower among VOCs, and 0.556 × 10 -9 s of carbon dioxide (CO 2 ) is faster for desorption. The results reveal that boron carbide can be utilized as a biosensor at room temperature for the analysis of exhaled VOCs from human breath.

Vicinal 4H and 6H-SiC0001 surfaces have been investigated using atomic force microscopy and cross-sectional high-resolution transmission electron microscopy. We observed the characteristic selfordering of nanofacets on any surface, regardless of polytypes and vicinal angles, after gas etching at high temperature. Two facet planes are typically revealed: (0001) and high index 112n that are induced by equilibrium surface phase separation. A 112n plane may have a free energy minimum due to attractive step-step interactions. The differing ordering distances in 4H and 6H polytypes imply the existence of SiC polytypic dependence on nanofaceting. Thus, it should be possible to control SiC surface nanostructures by selecting a polytype, a vicinal angle, and an etching temperature.

The thermal stability and the preservation of paramagnetic state of amorphous electroless NiP alloys are important for many industrial applications. The addition of third component (Me = Cu, Sn, or Sb) to NiP alloy should reduce the magnetic moment of precipitated ferromagnetic phase. The influence of Me on the thermal stability of ternary alloys is studied 9 Using differential scanning calorimetry, analysis of the crystallization kinetics is carried out. The remanence after annealing at different temperatures is presented.

We have conducted a study of the material and infrared-luminescence properties of Er-implanted GaN thin films as a function of annealing. The GaN films, grown by metal-organic chemical-vapor deposition, were coimplanted with Er and O ions. After implantation, the films were furnace annealed at temperatures up to 1,100°C. Following each annealing stage, the samples were examined by photoluminescence (PL) measurements and secondary ion-mass spectrometry (SIMS) analysis. In the as-implanted samples, no PL signal near 1,540 nm could be detected with either above-bandgap or below-bandgap excitation. Only after annealing at temperatures above 900°C was the 1,540-nm luminescence detectable. Annealing at higher temperatures resulted first in an increase and then a decrease in the PL-signal intensities. The SIMS data showed that large concentrations of Al, O, and C atoms entered into the GaN films with high-temperature annealing. The stoichiometric changes in the GaN appear responsible for the changes in the Er-related luminescence.

We have conducted a study of the material and infrared-luminescence properties of Er-implanted GaN thin films as a function of annealing. The GaN films, grown by metal-organic chemical-vapor deposition, were coimplanted with Er and O ions. After implantation, the films were furnace annealed at temperatures up to 1,100°C. Following each annealing stage, the samples were examined by photoluminescence (PL) measurements and secondary ion-mass spectrometry (SIMS) analysis. In the as-implanted samples, no PL signal near 1,540 nm could be detected with either above-bandgap or below-bandgap excitation. Only after annealing at temperatures above 900°C was the 1,540-nm luminescence detectable. Annealing at higher temperatures resulted first in an increase and then a decrease in the PL-signal intensities. The SIMS data showed that large concentrations of Al, O, and C atoms entered into the GaN films with high-temperature annealing. The stoichiometric changes in the GaN appear responsible for the changes in the Er-related luminescence.

High temperature in-situ Hall effect measurements in CdTe single crystals grown by different techniques at 500-1,200 K under well-defined Cd and Te vapor pressure were made. It was established that native point defects (PD) Cd 21 i and V 21 Te are dominant at T . 770 K in Cd-rich CdTe. Their formation enthalpies were determined (DH V 21 Te 5 1.3 eV; DH Cd 21 i 5 2.5 eV). It was shown that V 21 Te dominate at low temperatures and Cd 21 i begin to prevail at T . 930 K. In Te-saturated CdTe at heating up to ;800 K, the hole density was Te vapor pressure independent. At higher temperatures (HT), the conductivity changed to intrinsic type, turning then into n-type. The results were explained in the framework of Kro ¨ger's quasichemical formalism assuming the presence of an electrically active foreign point defect, the oxygen acceptor. The PD structure modeling demonstrated satisfactory agreement with experimental results both for temperature and component vapor pressure dependencies.

In this paper, the impact of defects (donor and acceptor traps) which are generated at the Si/SiO 2 interface and in semiconductor bulk, when the gate oxide is exposed to a high electric field stress (HEFS), on n-channel MOS and VDMOS transistors electrical characteristics is analysed and simulated. Taking the advantage of simulation, it was shown how and why the generated traps affect on n-channel MOS and n-channel VDMOS electrical characteristics. 1

This paper considers Ti-based carbo-nitride (TiCN) coatings deposited by Cathodic Arc Deposition (CAD/Arc-PVD) on Ti-6Al-4V alloy to improve its mechanical properties. The low-weight TiCN compounds are a competitive candidate for aerospace and the automotive industry, serving as protective coatings, improving hardness, and increasing the wear resistance of the treated elements. Despite the observed higher hardness values, these compounds also exhibit low friction coefficient (CoF) values. The structure, the morphology, and the composition of these coatings, analysed by XRD, XPS, AFM, and nanoindentation, are discussed in relation to their tribological properties.

In this work, the energy band alignments of heterostructures of 2D materials are studied, where these are crucial for various device applications. Using density functional theory (DFT), we consider heterostructures of Black Phosphorus (BP) with transition metal dichalcogenides (MX2), where M = Molybdenum (Mo), Tungsten (W), Hafnium (Hf) and X = Sulphide (S), Selenide (Se), and, specifically, the effects of charge redistribution and associated electrostatic fields on the band alignments beyond the electron affinity rule, as well as band tunability via applied layer-normal electric fields, applied strain, and layer engineering in BP/MoS2. BP is a material with high mobility, mechanical flexibility, and is also sensitive to the number of BP layers. Absent such tuning, calculations for BP combined with the more electronegative materials result in a staggered (Type II) alignment for MoS2, and a broken gap (Type III) alignment for HfSe2, and HfS2. Calculation for BP with less electronegative materials, WSe2, MoSe2 and WS2 materials result in straddling (Type I) alignment, with a direct gap for WSe2 and MoSe2, and an indirect gap for WS2. The amount of charge redistribution between layers and associated variations from the electron affinity rule increase going from Type I to Type II to Type III, where the band alignment becomes significantly pinned in the latter case by the creation of mobile charge carriers. With such tuning, these band alignments can then be altered quantitatively and qualitatively.

This study investigates the dielectric behavior of polyvinyl alcohol (PVA) com-
posites incorporating FeGaInS 4 layered crystals as fillers at varying weight con-
centrations (1 wt.%, 3 wt.%, 5 wt.%, and 8 wt.%), synthesized using the solution
mixing method. The layered structure of FeGaInS₄ facilitates distinctive inter-
facial interactions with the polymer matrix, potentially augmenting dielectric
properties. Structural characterization was performed using X-ray diffractometry
and Fourier-transform infrared (FTIR) spectroscopy, while dielectric properties
were assessed via dielectric spectroscopy across different filler concentrations,
temperatures, and frequencies of applied alternating current. FTIR analysis elu-
cidated polymer-filler interactions, and dielectric spectroscopy results demon-
strated an increase in dielectric permittivity with temperature and a decrease
with frequency. Notably, the composite with 1 wt.% filler exhibited the highest
dielectric permittivity, attributed to the uniform dispersion of FeGaInS₄ crystals
within the matrix, enhancing interfacial polarization. The tangent loss angle was
observed to rise with temperature, corresponding to increased electrical conduc-
tivity. The Correlated Barrier Hopping (CBH) model was applied to evaluate
system parameters (s, WM, Rω, and N) for PVA and FeGaInS₄-based composites
at 293 K and 313 K under a frequency of 2 × 10 3 Hz, indicating charge transport
via electron hopping between localized states mediated by zone and hopping
conductivity mechanisms. Activation energy values were determined for com-
posites with varying filler concentrations, ranging from 0.71–0.30 eV for pure
PVA to 1.46–0.85 eV (1 wt.%), 0.57–0.27 eV (3 wt.%), 0.71–0.30 eV (5 wt.%), and
0.70–0.34 eV (8 wt.%). The findings reveal that increasing the semiconductor filler
content enhances electrical conductivity, underscoring the potential for optimiz-
ing the dielectric and electrical properties of PVA composites through controlled
filler concentration

Electro-conductive hydrogel is a new composite hydrogel with high electrical conductivity, extraordinary mechanical properties, and controllability. It can be equipped with specific materials to obtain specific properties, which has attracted considerable research attention due to its wide range of application as a biomaterial in the biomedical engineering field. It can be used as a patch to promote healing and as a dressing for burns and pressure wounds. In pharmaceutical science, it is widely studied as a carrier of targeted and quantitative drug release. In surgery, it can serve as a cell scaffold for implantable therapy. Currently, increasing research is focusing on the development of sensors as simulated skin for robots, as well as in health monitors for human activity and well-being. In this review, we summarize the classification and selection of conductive mediums, natural polymer hydrogel matrices, and the application of electro-conductive hydrogels in the fields of bioengineering and biomedicine. We delve into the properties of different conductive mediums and the principle of combining different hydrogel matrices and discuss the advantages and disadvantages of emerging composite hydrogels. Our focus extends to the forefront of conductive hydrogel research in various fields, while also elucidating the current problems and challenges in terms of performance integration, preparation process and practical applications.

Superconductivity is a collective quantum phenomenon that is inevitably suppressed in reduced dimensionality. Questions of how thin superconducting wires or films can be before losing their superconducting properties have important technological ramifications and go to the heart of understanding formation, coherence, and robustness of the superconducting state in quantum confined geometries. Here, we exploit quantum confinement of itinerant electrons in a soft metal (Pb), to stabilize atomically-flat superconductors with lateral dimensions of mm and vertical dimensions of only a few atomic layers. They show no indication of defect-or fluctuation-driven suppression of superconductivity and support macroscopic super-currents of up to ∼10% of the depairing current density. The hardness of the critical state can be attributed to the presence of intrinsic vortex traps that are stabilized by quantum confinement. The study presents a conceptually appealing picture of a model nano-scale superconductor with calculable critical state properties, suggesting the possibility of achieving and exploiting superconductivity in the ultimate low-dimensional limit.

The electronic structure of Ba3Ta6Si4O26 was calculated using the generalized gradient approximation (GGA). The band gap of Ba3Ta6Si4O26 was theoretically estimated to be 2.92 eV. Both of the upper valence and lower conduction bands mainly consist of Ta 5d and O 2p states, and these states are well hybridized. From the band calculation, it was found that excited electrons from the valence band to the conduction band have a high mobility toward the c-axis of the crystal. Furthermore, the theoretical refractive index of Ba3Ta6Si4O26 was calculated to be 1.77 from the complex dielectric function.

This study describes the preparation of ZnO based varistors by sintering a mixture of ZnO powders with small quantities of bismuth oxide at a relatively high temperature. We also investigate the influence of Bismuth oxide addition on the microstructure of zinc oxide based varistors. The ceramic microstructure was characterised by measuring density, using SEM, X-ray diffraction and EDS. Bismuth oxide doping resulted in liquid phase sintering, rapid densification and grain growth. In this study ZnO powder was prepared from zinc recovered from spent zinc carbon battery. Use of recycled zinc from waste has made the study important from both economical and environmental point of view.

We studied the sensitivity of the steady-state electron transport in GaN to variations in the important material parameters related to the band structure. We found (a) that an increase in the lowest conduction-band-valley effective mass leads to a lowering and broadening of the peak in the velocity-field characteristic, as well as to an increase in the field at which the peak occurs; (b) that increases in the upper conduction-band-valley effective masses dramatically decrease the saturation drift velocity, with very little other effect; (c) that increased nonparabolicity of the lowest conduction-band valley leads to a broadening and shifting to higher electric fields of the peak in the velocityfield characteristic; (d) that increases in the intervalley energy separation lead to moderate increases in the peak drift velocity; and (e) that increases in the degeneracy of the upper conduction-band valleys leads to a moderate decrease in the saturation drift velocity.

An electrolytic plate ultra-thin gold (UTG) over 2.5 to 5 microns(µ) pure nickel is an economical and environmentally friendly printed circuit board (PCB) finish, tested over 100,000M 2. UTG was tested for solderability under double stress of an 8hour heat and humidity test followed by 2X IR reflow passes. A test lot of 100,500 plated through holes, with 1 to 28 nanometre (nm) gold thickness, wave soldered with SAC leadfree solder, showed 99.93% holes completely filled. UTG with 5 nm gold thickness, showed a bond pull strength is 6.75gf for aluminium wire (Al) bonding and no increase of resistance after 1 million membrane keypad operations. At 14 nm thickness, the gold wire (Au) bond pull strength averaged at 8 gf. The manufacturing process is standard till PCB panel outer layers pattern copper, followed by an electrolytic nickel layer of 2.5 to 5µ on copper. Secondary imaging is done to cover all non-solderable and non-contact areas, to reduce the gold plating area. The panels are then plated with gold of 5 nm or as required, and etched. Overhang of 2.5 to 3 µ on a 5 µ base copper is achieved. At 5 nm gold thickness, it uses 90% less gold than consumed in electroless nickel-immersion gold (ENIG) process. It reduces chemistry/pollution treatment costs by eliminating the ENIG processes of tin plating/de-plating, activation, electroless nickel, and immersion gold. The reduced gold consumption of this finish of 90%can save more than 1 million Tons greenhouse gasses per annum by substituting ENIG.

An oxygen doped microcrystalline silicon (pc-Si) deposition process is developed by mixing small amounts of nitrous oxide (N20) with silane (Sill 4) in a rapid thermal chemical vapor deposition (RTCVD) reactor. The effects of oxygen doping on the properties ofRTCVD pc-Si films are studied. Experimental results show that the RTCVD process provides high deposition rates for ~tc-Si and polycrystalline silicon (polySi) films at elevated deposition temperatures and pressures. The surface roughness of the RTCVD pc-Si films can be significantly reduced compared to that of conventional LPCVD polySi films. Steep side walls can be realized due to the small grain size of the ~c-Si films. The sheet resistance of BF 2 doped pc-Si films is slightly higher than that of BF 2 doped polySi films, whereas sheet resistances of P and As doped pc-Si films are much higher than those of the corresponding P and As doped polySi films. Measurements of the catastrophic breakdown strength of metal-oxide-semiconductor (MOS) capacitors indicate that the quality of gate electrodes fabricated using pc-Si is improved relative to that of MOS capacitors fabricated using polySi gate electrodes.

A modified thermoset polymer resin (PR) is evaluated as a form of alternative packaging material to traditional epoxy. It is understood that the thermoset cross-links to a higher degree at high temperature. Hence, its mechanical properties can be improved by changing treatment duration and temperature, rendering the material mechanically stronger for application temperatures beyond 300°C. Material strength was evaluated through a modified compressive testing setup which shows neat PR is comparable to epoxy. Concurrently, adhesion to silicon die and ceramic substrate were evaluated by means of bond shear using the DAGE-4000 shear tester both at room temperature and elevated temperature. Bond shear strength of PR is observed to be higher at room temperature as compared to elevated temperatures when bonded to Silicon (Si) and Alumina (Al 2 O 3 ), a phenomenon which can be attributed to mismatches in coefficient of thermal expansions (CTE). For high pressure only applications, PR is a good alternative. Pre-and post-pressure loading analysis was carried out by forming an encapsulation analogous to that of a glob top on DIP packages. Observation shows no crack formation, indicating that the material is suitable for high pressure loading up to 207 MPa. For high pressure and high temperature applications (HPHT), pure PR is good up to 250°C at 25 kPsi (172 MPa).

A modified thermoset polymer resin (PR) is evaluated as a form of alternative packaging material to traditional epoxy. It is understood that the thermoset cross-links to a higher degree at high temperature. Hence, its mechanical properties can be improved by changing treatment duration and temperature, rendering the material mechanically stronger for application temperatures beyond 300°C. Material strength was evaluated through a modified compressive testing setup which shows neat PR is comparable to epoxy. Concurrently, adhesion to silicon die and ceramic substrate were evaluated by means of bond shear using the DAGE-4000 shear tester both at room temperature and elevated temperature. Bond shear strength of PR is observed to be higher at room temperature as compared to elevated temperatures when bonded to Silicon (Si) and Alumina (Al2O3), a phenomenon which can be attributed to mismatches in coefficient of thermal expansions (CTE). For high pressure only applications, PR is a good ...

A lead-free glass frit paste as a die-attach material for high-temperature microelectronic application is proposed in this study. The glass paste containing Bi-based powder with a moderate amount of solvent was used for joining Si dice on ceramic substrates without any metallization preparation for either of the bonding surfaces. The die was bonded to a ceramic substrate at 430°C for 10 min. The study focuses on the mechanical and microstructural characterization of the joints with Si dice on two different types of ceramic substrate. Shear strength measurements were carried out at both ambient and 250°C to evaluate room-and high-temperature performance. Furthermore, the effect of aging at 300°C for 500 h on the mechanical properties is presented. The results of the mechanical and microstructural characterization demonstrate that low-temperature glass frit bonding is an effective die-attach method for harsh-environment electronic packaging.

The study analyses the impact of temperature on the performance of TFETs. In this paper, we propose two InGaAs TFETs and compare their figure of merits with silicon based TFET. Various figure of merits such as subthreshold swing, threshold voltage, ION/IOFF and DIBL are analyzed for temperature range from -25°C to 100°C. In this study, the simulation tool used is silvaco. The comparison of single metal and dual metal InGaAs TFET with Silicon TFET has been reported through this work. The results show that dual metal InGaAs TFET is better than single metal InGaAs and Silicon TFET.

Desde la perspectiva de la escuela de procesos del Aprendizaje Organizacional (AO), el presente trabajo se propone identificar las variables vinculadas a la Capacidad de Absorcion (CA), caracterizar a las empresas en terminos de estas variables, e identificar la existencia o no de asociacion entre las variables de capacidades y la variable tamano de empresa. Se realiza un estudio descriptivo-exploratorio en 103 empresas argentinas de software, aplicandose el coeficiente de correlacion de Spearman para la verificacion de la asociacion entre el tamano de empresa y las variables de capacidades propuestas. Los resultados arrojan diferencias significativas por tamano para las herramientas de software utilizadas, nivel de procesos, certificacion de normas de calidad e indicadores para medir la satisfaccion de los clientes, siendo las empresas grandes quienes presentan niveles superiores. No se identifican diferencias significativas por tamano para las demas variables de capacidades en est...

Among ecological solders the SIAC (silver-indium-tin-copper) alloys seemed to be the promising because of their properties. In this paper the results of Ag-In-Sn-Cu electrical conductivity measurements are performed as well as polynomial regression of the same. These results are obtained for different temperature regimes and conditions.

Phase transition temperatures of selected ascast alloys from ternary Cu-Al-Ag system with overall compositions situated alongside vertical section with equal molar ratios of Ag and Cu were experimentally investigated using differential thermal analysis. Microstructures of the as-cast samples were analyzed using scanning electron microscopy with energy-dispersive spectrometry. Experimentally obtained results were compared with the results obtained by thermodynamic calculation of phase equilibria according to CALPHAD approach.

Here, we report a previously unreported low-temperature curable barium strontium titanate (Ba X Sr 1-X TiO 3 ) or BST dielectric nanoparticle ink which shows a high dielectric tunability for printed electronics/additive manufacturing applications. The newly formulated BST ink is optimized to print in aerosol jet printers and can be cured at 150°C, which will allow the fabrication of tunable radio-frequency (RF) and microwave (MW) devices on a wide range of flexible substrates. Characterization of high-frequency dielectric properties showed a high dielectric tunability (~ 15% at 10 GHz with 10 V/µm) and a high dielectric constant (~ 16 at 10 GHz). The linear-reversible tunability, which is very important for tunable devices, was confirmed by the tunability testing at 10 GHz. Characterization of temperature-dependent dielectric properties found < 10% variations of the dielectric constant at 10 GHz from -50°C to 125°C for this BST ink. Detailed information on BST nanoparticle characterization, ink formulation and characterization of dielectric properties is discussed.

Here, we report a previously unreported low-temperature curable barium strontium titanate (Ba X Sr 1-X TiO 3 ) or BST dielectric nanoparticle ink which shows a high dielectric tunability for printed electronics/additive manufacturing applications. The newly formulated BST ink is optimized to print in aerosol jet printers and can be cured at 150°C, which will allow the fabrication of tunable radio-frequency (RF) and microwave (MW) devices on a wide range of flexible substrates. Characterization of high-frequency dielectric properties showed a high dielectric tunability (~ 15% at 10 GHz with 10 V/µm) and a high dielectric constant (~ 16 at 10 GHz). The linear-reversible tunability, which is very important for tunable devices, was confirmed by the tunability testing at 10 GHz. Characterization of temperature-dependent dielectric properties found < 10% variations of the dielectric constant at 10 GHz from -50°C to 125°C for this BST ink. Detailed information on BST nanoparticle characterization, ink formulation and characterization of dielectric properties is discussed.

An electrolytic plate ultra-thin gold (UTG) over 2.5 to 5 microns(µ) pure nickel is an economical and environmentally friendly printed circuit board (PCB) finish, tested over 100,000M 2. UTG was tested for solderability under double stress of an 8hour heat and humidity test followed by 2X IR reflow passes. A test lot of 100,500 plated through holes, with 1 to28 nanometre (nm) gold thickness, wave soldered with SAC leadfree solder, showed 99.93% holes completely filled. UTG with 5 nm gold thickness, showed a bond pull strength is 6.75gf for aluminium wire (Al) bonding and no increase of resistance after 1 million membrane keypad operations. At 14 nm thickness, the gold wire (Au) bond pull strength averaged at 8 gf. The manufacturing process is standard till PCB panel outer layers pattern copper, followed by an electrolytic nickel layer of 2.5 to 5µ on copper. Secondary imaging is done to cover all non-solderable and non-contact areas, to reduce the gold plating area. The panels are then plated with gold of 5 nm or as required, and etched. Overhang of 2.5 to 3 µ on a 5 µ base copper is achieved. At 5 nm gold thickness, it uses 90% less gold than consumed in electroless nickel-immersion gold (ENIG) process. It reduces chemistry/pollution treatment costs by eliminating the ENIG processes of tin plating/de-plating, activation, electroless nickel, and immersion gold. The reduced gold consumption of this finish of 90%can save more than 1 million Tons greenhouse gasses per annum by substituting ENIG.

Structural studies on In 2 S 3 thin films deposited by vacuum thermal evaporation on glass substrates at a temperature of 240 o C, followed by annealing at 330°C and 400°C are presented. It was shown that the films were of amorphous in nature before annealing and after annealing the films became polycrystalline and showed β-In 2 S 3 structure. The grain size increased and followed the usual crystal growth process as the annealing temperature increased. The annealing-induced changes of surface roughness were characterized by atomic force microscopy. In 2 S 3 naniesionych metodą termicznego osadzenia na szkło w próżni w temperaturach od 240 o C i kolejnym wygrzewaniem w temperaturach 330 o C i 400 o C. Ustalono że warstwy miały amorficzną naturę przed wygrzewaniem, po wygrzewaniu wykazywały strukturę polikrystaliczną typu β-In 2 S 3 . Rozmiar ziaren powiększał się na skutek aktywnej nuklearyzacji i to przyczyniało się do zwykłej krystalizacji ze wzrostem temperatury. Zmiany zostały przeanalizowane za pomocą AFM. (Wpływ obróbki temperaturowej na termicznie naparowane cienkie warstwy In 2 S 3 ).

In the present work we demonstrate the possibility of using the photoinduced current transient spectroscopy (PICTS) method to study the defects in Cu(In,Ga)(S,Se) 2 films which can be used as an absorber layer in solar cells (SCs). The conducted experiments enable one to determine the parameters (activation energies and effective capture cross-sections) of the defects revealed in the films under study.

Mg 2 Si has attracted interest as a potential thermoelectric material that can convert waste heat into electricity. To improve thermoelectric performance of Mg 2 Si, Al/Mg 2 Si composite materials with nominal composition of xAl/Mg 2 Si (x = 0.25, 0.5, 0.75, 1.0, or 1.5) were fabricated, i.e., an Al metal phase was introduced to an Mg 2 Si matrix. Reflecting an increase in the electrical conductivity and a decrease in the Seebeck coefficient with increasing x, the power factor was successfully enhanced by the incorporation of the Al phase. The increase in electrical conductivity was discussed in terms of electron carrier density and carrier mobility.

Nanostructured Zinc oxide (ZnO) was synthesized via a ball milling for 10 hours using high energy planetary ball mill. Phase purity and homogeneity of all the samples have been investigated by X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FE-SEM). All the diffraction peaks can be indexed to the hexagonal phase ZnO with hexagonal symmetry (space group P6 3 mc). Average crystallite size was observed to be 20 nm. There was a remarkable suppression in thermal conductivity (κ) compared to the bulk values by a factor of ~50 at room temperature. This suggests to the possibility of using nanostructured ZnO as a prospective room temperature thermoelectric material.

Al (100 nm)/n-ZnO (40 nm)/p-CuAlO x :Ca (100 nm, 200 nm, 300 nm) diodes were fabricated on polyethylene terephthalate substrates at room temperature using a sputtering technique. No additional heat treatment was performed on the fabricated devices. Increase of the diode layer thickness reduced the on-current and leakage-current levels simultaneously, which led the rectification ratio to first increase and then decrease as the p-layer thickness increased. The ultraviolet (UV) response of the diode was also investigated under irradiation at 365 nm. The n + -ZnO:Al (100 nm)/n-ZnO (40 nm)/p-CuAlO x :Ca (200 nm) diode exhibited photocurrent/ leakage current ratio of 1.03 9 10 3 and responsivity of 0.64 A/W at reverse bias of À6 V when measured in flat status. The corresponding photocurrent/ leakage current ratio and responsivity were 7.99 9 10 2 and 0.65 A/W, respectively, for an outwardly bent diode with 5.5 cm radius of curvature. The increases of current levels under bending are attributed to the decreases of series resistance for the diode under tensile strain.

Hydroxyterminated polybutadiene (HTPB) based porous polyurethaneurea (PUU) membranes were prepared. The porosity was developed by incorporation of lithium chloride into polymer matrix with subsequent leaching of the same in hot water. Scanning electron microscopic analysis of the prepared membrane surfaces was performed. The pervaporation performance of the synthesized membrane was studied with aqueous 4-nitrophenol solution as feed. The effects of various parameters on 4-nitrophenol separation factor and total as well as 4-nitrophenol flux were studied. Polyurethaneurea membrane was found to permeate 4-nitrophenol selectively with high separation factors for the organic component. Pore size and number of pores on the surface of the membrane were calculated from SEM image of the membranes. Effects of pore size and porosity on pervaporation flux were also investigated.

A novel recognition method for selective determination of the hyoscine N-Butyl bromide (HBB), an antispasmodic agent for smooth muscles, was devised using extended gate field-effect transistor (EG-FET) as transducing unit. For this purpose a PVC membrane, containing hyoscine n-butyl-tetraphenyl borate ion-pair as recognition component, was coated on Ag/AgCl wire, which was connected to the extended metal gate. In optimal conditions, the linear range for HBB was 10 -8 -10 -5 molL -1 with limit of detection 1.7×10 -9 molL -1 . The proposed sensor was applied in real sample, it showed fast response with high accuracy, and therefore it could be used as HPLC detector in the pharmaceutical samples in quality control.

In this study we present the results of our calculations on the Neodymium Silver (AgNd) compound by performing ab initio total energy calculations within the generalized gradient approximation (GGA) in VASP package. Specifically, we have computed some basic physical properties, such as lattice constant, bulk modulus, second-order elastic constants (Cij), the electronic band structures, and phonon frequencies ,and compared with the available experimental and other theoretical findings

The reliability of chip scale package (CSP) components against mechanical shocks has been studied by employing statistical, fractographic, and microstructural research methods. The components having high tin (Sn0.2Ag0.4Cu) solder bumps were reflow soldered with the Sn3.8Ag0.7Cu (wt.%) solder paste on Ni(P)|Au-and organic solderability preservative (OSP)-coated multilayer printed wiring boards (PWBs), and the assemblies were subjected to the standard drop test procedure. The statistically significant difference in the reliability performance was observed: the components soldered on Cu|OSP were more reliable than those soldered on Ni(P)|Au. Solder interconnections on the Cu|OSP boards failed at the component side, where cracks propagated through the (Cu,Ni) 6 Sn 5 reaction layer, whereas interconnections on the Ni(P)|Au boards failed at the PWB side exhibiting the brittle fracture known also as "black pad." In the first failure mode, which is not normally observed in thermally cycled assemblies, cracks propagate along the intermetallic layers due to the strong strain-rate hardening of the solder interconnections in drop tests. Owing to strain-rate hardening, the stresses in the solder interconnections increase very rapidly in the corner regions of the interconnections above the fracture strength of the ternary (Cu,Ni) 6 Sn 5 phase leading to intermetallic fracture. In addition, because of strain-rate hardening, the recrystallization of the as-soldered microstructure is hindered, and therefore the network of grain boundaries is not available in the bulk solder for cracks to propagate, as occurs during thermal cycling. In the black pad failure mode, cracks nucleate and propagate in the porous NiSnP layer between the columnar two-phase (Ni 3 P ϩ Sn) layer and the (Cu,Ni) 6 Sn 5 intermetallic layer. The fact that the Ni(P)|Au interconnections fail at the PWB side, even though higher stresses are generated on the component side, underlines the brittle nature of the reaction layer.

To simulate more realistically the effects of strains and stresses on the reliability of portable electronic products, lead-free test assemblies were thermally cycled (-45°C/+125°C, 15-min. dwell time, 750 cycles) or isothermally annealed (125°C, 500 h) before the standard drop test. The average number of drops to failure increased when the thermal cycling was performed before the drop test (1,500 G deceleration, 0.5 ms half-sine pulse). However, the difference was not statistically significant due to the large dispersion in the number of drops to failure of the assemblies drop tested after the thermal cycling. On the other hand, the average number of drops to failure decreased significantly when the isothermal annealing was carried out before the drop test. The failure analysis revealed four different failure modes: (1) cracking of the reaction layers on either side of the interconnections, (2) cracking of the bulk solder, (3) mixed mode of component-side intermetallic and bulk solder cracking, and (4) voidassisted cracking of the component-side Cu 3 Sn layer. The assemblies that were not thermally cycled or annealed exhibited only type (1) failure mode. The interconnections that were thermally cycled before the drop test failed by mode (2) or mode (3). The drop test reliability of the thermally cycled interconnections was found to depend on the extent of recrystallization generated during the thermal cycling. This also explains the observed wide dispersion in the number of drops to failure. On the other hand, the test boards that were isothermally annealed before the drop testing failed by mode (4).

We report photoreflectance (PR) and photoluminescence (PL) investigations of the electronic and polarization properties of different aspect ratio (height/diameter) InGaAs quantum rods (QRs) embedded in InGaAs quantum wells (QWs). These nanostructures were grown by molecular beam epitaxy using As 2 or As 4 sources. The impact of the As source on the spectral and polarization features of the QR-and QW-related interband transitions was investigated and explained in terms of the carrier confinement effects caused by variation of composition contrast between the QR material and the surrounding well. Polarized PR and PL measurements reveal that the polarization has a preferential direction along the [ 110] crystal axis with a large optical anisotropy of about 60% in the (001) plane for high aspect ratio (4.1:1) InGaAs QRs. As a result, in PL spectra, the transverse magnetic mode dominated (110)-cleaved surfaces (TM [001] > TE [110] ), whereas the transverse electric mode prevailed for (110)-cleaved surfaces (TM [001] < TE [1 10] ). This strong optical anisotropy in the (001) plane is interpreted in terms of the hole wavefunction orientation along the [ 110] direction for high aspect ratio QRs.