Helge Heinrich

• University of Virginia

Insights into the roles of geometry, size, and composition on MnS inclusion dissolution to initiate pits in 304 L SS were obtained by combining operando and ex-situ electron microscopy, EDS, and atomistic modeling. The majority of thirty MnS on SS surface did not undergo dissolution even after over a week of exposure, and only a small number caused...

The late stages of precipitation in aluminum-rich Al –Ag alloys with silver contents from 3 at.% to 22 at.% were studied with transmission electron microscopy. Shapes, sizes, and arrangements of plates of the stable hexagonal Ag2Al phase forming on {111} planes of the f.c.c. matrix were analysed. The high-angle annular dark-field contrast in scanni...

Over the past several decades, intensive research on localized corrosion has allowed a deeper understanding of the origin of pit nucleation and growth in stainless steel exposed to atmospheric conditions. However, the problem of pitting corrosion triggered by dissolution of non-metallic particles (e.g., manganese sulfide "MnS") within the steel mat...

Reactions between boria (B2O3) and Yb2Si2O7 were studied via a series of idealized interfacial “well” tests. Boria oxidizes out of SiC/SiC ceramic matrix composites (CMCs) where BN is used as a fiber/matrix interphase and boron‐rich inclusions often serve as aids in the melt infiltration process. Borate phases are highly reactive and can react with...

A comparative investigation of the post-electroplating treatment influence on the gas detecting performances of single ZnO nanorod/nanowire (NR/NW), as grown by electrochemical deposition (ECD) and integrated into nanosensor devices, is presented. In this work, hydrothermal treatment (HT) in H2O steam and conventional thermal annealing (CTA) in a f...

NU-1000, a zirconium (Zr)-based metal-organic framework (MOF), is a promising candidate for heterogeneous catalysis, gas storage, electrocatalysis, and drug-delivery applications due to its large pore size and mesoporous structure. However, the synthesis of NU-1000 may produce another polymorph NU-901, which has a smaller average pore size and pore...

The frequency-dependent impedance of a metal/oxide/room temperature ionic liquid (RTIL) interface was separated into oxide layer (Cox) and double layer (Cdl) capacitances using electrochemical impedance spectroscopy (EIS). A pre-formed oxide of known initial thickness on Fe-20 at.% Cr was investigated in 1-ethyl-3-methylimidazolium methanesulfonate...

The atomic number contrast imaging technique reveals an increase in intensity at interfaces of a high and low-density material in case of relatively thick samples. Elastic scattering factors and absorption coefficients are incorporated in a probabilistic model to study atomic contrast occurring at the interface of two materials when the High-Angle...

Physical vapour deposited (PVD) zinc and zinc-magnesium coatings are compared to commercial galvanized zinc and zinc-magnesium-aluminum coatings in terms of bare metal corrosion when immersed in chloride-containing solution. A scanning vibrating electrode technique has been augmented to capture photographic images, in-situ, which complement the spa...

Water oxidation to dioxygen is an essential energy capture process in biological systems, and is a part of the oxygen-evolving complex. It continues to attract interest as a half-reaction portion in the electrochemical water-splitting to hydrogen and dioxygen in abiotic systems. There is a corresponding interest in improving the activity of non-pre...

Ordered arrays of semiconductor quantum dots may provide new electronic, optical, or thermoelectric functionalities. In this work, we create ordered two-dimensional arrays of Si-Ge quantum dots by heteroepitaxial growth on Si (001) with pre-patterned pits. Instead of growing the dots directly at elevated temperatures, we first grow conformal alloy...

We report here a quantitative method of Transmission Electron Microscopy (TEM) to measure the shapes, sizes and volumes of nanoparticles which are responsible for their properties. Gold nanoparticles (Au NPs) acting as nucleating agents for the electroless deposition of silver NPs on SU-8 polymers were analyzed in this project. The atomic-number co...

Gold black is a highly porous, extremely fragile, infrared-absorbing film used primarily as a coating for bolometers. Long term stability of its absorbance is a significant practical concern. This paper reports on the aging of morphological, electrical, and optical properties of gold black samples prepared with different initial porosities. An obse...

Heusler alloy, Ni2MnGa, and its off-stoichiometric solid solutions have great potential applications in refrigeration technology due to their magnetocaloric effect (MCE), which can be strongly influenced by martensitic phase transformations and related crystallography. In this study, five polycrystalline alloys with nominal compositions of Ni2+x Mn...

Transmission Electron Microscopy is used as a quantitative method to measure the shapes, sizes and volumes of gold nanoparticles created at a polymeric surface by three different in situ synthesis methods. The atomic number contrast (Z-contrast) imaging technique reveals nanoparticles which are formed on the surface of the polymer. However, with ce...

A solid-to-solid, U-7wt.%Mo vs. Mg diffusion couple was assembled and annealed at 550°C for 96 hours. Themicrostructurein the interdiffusion zone and the development of concentration profiles were examined via scanning electron microscopy, transmission electron microscopy (TEM) and X-ray energy dispersive spectroscopy. A TEM specimen was prepared a...

We have gained insight into the internal degree of atomic disorder in isolated size-selected Fe nanoparticles (NPs) (∼2–6 nm in size) supported on SiO2/Si(111) and Al2O3(0001) from precise measurements of the low-energy (low-E) part of the phonon density of states [PDOS, g(E)] via 57Fe nuclear resonant inelastic x-ray scattering (NRIXS) combined wi...

An SS304 + 10 wt pct Al (with a nominal composition of Fe-18Cr-8Ni-10Al by wt pct and corresponding to Fe-17Cr-6Ni-17Al by at. pct) coating was deposited on a 304-type austenitic stainless steel (Fe-18Cr-8Ni by wt pct) substrate by the magnetron sputter-deposition technique using two targets: 304-type stainless steel (SS304) and Al. The as-deposite...

We report that porous silicon acoustic Bragg reflectors and AlN-based transducers can be successfully combined and processed in a commercial solidly mounted resonator production line. The resulting device takes advantage of the unique acoustic properties of porous silicon in order to form a monolithically integrated bulk acoustic wave resonator.

A new approach of chemical bath deposition (CBD) of SnO2 thin films is reported. Films with a 0.2 μm thickness are obtained using the multi-dip deposition approach with a deposition time as little as 8–10 min for each dip. The possibility of fabricating a transparent conducting oxide layer of Cd2SnO4 thin films using CBD is investigated through suc...

We report results of Monte Carlo simulation of a model which mimics certain aspects of electroless deposition of metals on polymeric surfaces. In the proposed model growth germinates from certain ``active'' particles residing on a flat surface. Further growth occurs via sticking of a diffusing particle while it is within the range of one of these a...

We report on the quantitative analysis of electrolessly deposited Au and Ag nanoparticles (NPs) on SU8 polymer with the help of High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy (HAADF-STEM) in tilt series. Au NPs act as nucleating agents for the electroless deposition of silver. Au NPs were prepared by attachingAu^3+cations t...

We report here a quantitative method of Transmission Electron Microscopy (TEM) to measure the shapes, sizes and volumes of nanoparticles which are responsible for their properties. Gold nanoparticles (Au NPs) acting as nucleating agents for the electroless deposition of silver NPs on SU-8 polymers were analyzed in this project. The atomic-number co...

ReB2 was recently reported to exhibit high hardness and low compressibility, which both are strong functions of its stoichiometry, namely Re to B ratio. Most of the techniques used for ReB2 synthesis reported 1:2.5 Re to B ratio because of the loss of the B during high temperature synthesis. However, as a result of B excess, the amorphous boron, lo...

Electrodeposition is a low temperature and low cost growth method of high quality nanostructured active materials for optoelectronic devices. We report the electrochemical preparation of ZnO nanorod/nanowire arrays on n-Si(1 1 1) and p-Si(1 1 1). The effects of thermal annealing and type of substrates on the optical properties of ZnO nanowires elec...

Chemical bath deposition of CdO thin films using three different complexing agents, namely ammonia, ethanolamine, and methylamine is investigated. CdSO4 is used as Cd precursor, while H2O2 is used as an oxidation agent. As-grown films are mainly cubic CdO2, with some Cd(OH)2 as well as CdO phases being detected. Annealing at 400 °C in air for 1 h t...

The changes induced in the structure and chemical state of size-selected Pt nanoparticles (NPs) supported on ultrathin SiO2 films upon exposure to oxygen have been investigated by atomic force microscopy (AFM), transmission electron microscopy (TEM), in situ X-ray photoelectron spectroscopy (XPS), and temperature-programmed desorption (TPD). For lo...

We observed a huge volume expansion of aligned single walled carbon nanotube (SWNT) arrays accompanied by structural transformation during electrical breakdown in vacuum. The SWNT arrays were assembled between prefabricated Pd source and drain electrodes of 2 \mu m separation on Si/SiO_2 substrate via dielectrophoresis. At high electrical field, th...

This study presents a solid state surface engineering technique for forming a composite surface layer on aluminum to improve surface hardness and wear resistance without sacrificing the ductility and conductivity of the bulk. Friction stir processing (FSP) was used to stir and mix sub-micro-size Al2O3 and SiC particles into the surface of an alumin...

In this paper, a single ZnO microwire-based photodetector for the monitoring of ultraviolet (UV) radiation is described. Single crystal ZnO microwires were synthesized using a chemical vapor deposition (CVD) on the Si or Al2O3 substrate. The UV photodetector was fabricated by using in-situ lift-out method in a focused ion beam system to manipulate...

We report pattern formation using a slippery ballistic deposition (SBD) model where growth germinates from a single site or from sites distributed periodically on a lattice. By changing the sticking probability p(s) and choosing systems with different lattice constants and symmetries, we demonstrate that a variety of patterns can be generated. Thes...

Gold nanoparticles(Au-NPs) act as nucleation sites for electroless deposition of silver on functionalized SU8 polymeric surfaces. Here we report the nanoscale morphology of Au and Ag nanoparticles as studied by Transmission Electron Microscopy (TEM). Scanning TEM with a high-angle annular dark-field detector is used to obtain atomic number contrast...

This paper describes a methodology based on hollow-cone dark-field (HCDF) transmission electron microscopy (TEM) to study dislocation structures in both nano- and micro-crystalline grains. Although the conventional approach based on a two-beam condition has been commonly used to acquire weak-beam dark-field (WBDF) TEM images for dislocation structu...

Uniaxially aligned polysynthetically twinned two-phase TiAl/Ti3Al material is produced by induction zone melting and deformed in uniaxial compression. Above 1000 K the strain rate sensitivity is independent of the lamellar orientation and increases strongly with increasing deformation temperature. Results for the strain rate sensitivity parameters...

In Scanning Transmission Electron Microscopy (STEM) the High-Angle Annular Dark-Field (HAADF) signal increases with atomic number and sample thickness, while dynamic scattering effects and sample orientation have little influence on the contrast. The sensitivity of the HAADF detector for a FEI F30 transmission electron microscope has been calibrate...

The alloy Ti-48.6Al-l.9Cr-l.9Nb-IB with an equiaxed γ microstructure, obtained by heat treatment at 1200°C for 4 h, and with a lamellar mi ero structure, obtained by heat treatment at 1380°C for 1 h, is characterized by compression tests and transmission electron microscopy. A lower activity of superdislocations and a more frequent pinning of ordin...

This article presents a systematic study of the formation and thermal stability of Pt oxide species on size-selected Pt nanoparticles (NPs) supported on SiO2, ZrO2, and TiO2 thin films. The studies were carried out in ultrahigh vacuum (UHV) by temperature-dependent X-ray photoelectron spectroscopy (XPS) measurements and ex situ transmission electro...

In this paper we report the synthesis of ZnO nanowires via chemical vapor deposition (CVD) at 650 °C. It will be shown that these nanowires are suitable for sensing applications. ZnO nanowires were grown with diameters ranging from 50 to 200 nm depending on the substrate position in a CVD synthesis reactor and the growth regimes. X-ray diffraction...

ZnO nanowires were synthesized by the CVD procedure and have been investigated by SEM, TEM, SAED, Raman, and cw PL spectroscopy. The fabrication of an ultraviolet (UV) photoconductive detector based on single ZnO nanowire (100 nm in diameter) is presented. This nanostructure detector is prepared in an Focused Ion Beam (FIB) set-up by using nanodepo...

of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

We report on the effects of post-growth hydrothermal treatment and thermal annealing on properties of vertically aligned ZnO nanowires arrays (NWs). The samples were electrochemically deposited (ECD) on indium–tin oxide (ITO)-coated glass substrates and subjected to post-growth hydrothermal treatment (HT) at 150 °C and, for the purpose of compariso...

We report lattice Monte Carlo (MC) simulation studies of deposition of metallic silver on randomly distributed gold nano clusters on a polymeric surface. The gold nano-clusters act as seeds for further deposition of silver atoms. We assume ballistic growth for the growth of metallic silver on gold clusters but treat the lateral growth (which eventu...

Silver was deposited onto the functionalized surface of polymeric SU-8 where gold nanoparticles (Au-NPs) act as nucleation sites using electroless metallization chemistry. Here we report on the evolution of the nanoscale morphology of deposited Ag studied by Transmission Electron Microscopy (TEM). In TEM of sample cross sections correlations betwee...

The development of cost-effective and low-temperature synthesis techniques for the growth of high-quality zinc oxide thin films is paramount for fabrication of ZnO-based optoelectronic devices, especially ultraviolet (UV)-light-emitting diodes, lasers and detectors. We demonstrate that the properties, especially UV emission, observed at room temper...

The effect of pretreatment conditions on the oxidation state and activity of micelle-synthesized Pt nanoparticles supported on ZrO2 was studied for methanol decomposition and oxidation reactions. An O2-pretreatment is observed to be effective for producing clean, stable, and active nanoparticles. Pt-oxide species formed during such pretreatments we...

This article discusses the performance of ZrO2-supported size-selected Pt nanoparticles for the decomposition of methanol, ethanol, 2-propanol, and 2-butanol. The potential of each alcohol for the production of H2 and other relevant products in the presence of a catalyst is studied in a packed-bed mass flow reactor operating at atmospheric pressure...

We have measured the phonon density of states (PDOS) of isolated bcc and fcc Fe _x Au _1-x alloy nanoclusters (NCs) by nuclear resonant inelastic x-ray scattering. Drastic deviations were observed with respect to the PDOS of bulk Fe–Au alloys. Important information on the structure and thermodynamic properties of these NCs was o...

In this paper, we describe hollow-cone dark field (HCDF) transmission electron microscopy (TEM) imaging, with a slightly convergent beam, as an improved technique that is suitable to form high contrast micrographs for nanocrystalline grain size quantification. We also examine the various factors that influence the HCDF TEM image quality, including...

For development of individual ZnO microwire in hydrogen sensors an environmentally benign synthesis process and fabrication route are required. Here we report a synthesis route for ZnO microwires using vapour phase process. Furthermore, our synthesis technique permits microwires to be transferred to other substrates. This offers the possibility of...

The Fe-projected phonon density of states PDOS of monolayer-thick films of self-assembled, size-selected, isolated 57Fe 1−x Pt x alloy nanoclusters NCs height: 2 nm, diameter: 8 nm supported on flat SiO2 / Si111 substrates has been measured by nuclear resonant inelastic x-ray scattering. The samples were characterized by atomic force microscopy AFM...

Chemical bath deposition of ZnO thin films using six different complexing agents, namely ammonia, hydrazine, ethanolamine, methylamine, triethanolamine and dimethylamine, is investigated. As-grown films were mainly ZnO(2) with a band gap around 4.3 eV. Films annealed at 400 degrees C were identified as ZnO with a band gap around 3.3 eV. X-ray diffr...

This study presents a solid state surface engineering process to form a nanocomposite layer on aluminum surface. Friction stir processing (FSP) was used to stir and mix nano-sized Al2O3 particles into a commercially pure aluminum surface to form an Al-Al2O3 nanocomposite layer of up to several millimeters thick. Compared with a non-processed alumin...

We present a method of self-assembly of densely packed and aligned bilayer ZnO nanorod arrays in a hydrothermal synthesis process. The alkali hydrothermal environment first induced the growth of hydrotalcitelike zincowoodwardite plates, which provide a lattice-matched surface for the self-assembly of ZnO nanorod arrays. The high packing density of...

The combination of long term aging studies and molecular dynamics (MD) simulations has been successfully used to explain the time dependent, hierarchical assembly of ceria nanoparticles (CNPs). When the CNPs were aged in as-synthesized condition at room temperature, in water, it was observed that the individual 3-5 nm CNPs result in octahedral supe...

An ultraviolet photosensor has been successfully constructed by the in situ lift-out method in a focused ion beam system. The prototype consists of individual naturally self-assembled crossed ZnO nanorods grown by an aqueous solution process. The current–voltage (I–V) characteristics show linear behavior. The photosensor exhibits a response of ∼15...

In-situ boron doping of CdS using chemical-bath deposition (CBD) is reported. The effect of B doping on optical properties, as well as electrical properties, crystal structure, chemistry, and morphology of CdS films is studied. We present successful approach towards B doping of CdS using CBD where a resistivity as low as 1.7 x10(-2) Omega cm and a...

We have developed a simple solution process to synthesize tin oxide nanorods. The influence of precursors and the reaction temperature on the morphology of SnO2 is investigated. SnO2 nanorods are characterized by X-ray diffraction (XRD). transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Raman spectroscopy. The as-grown...

Tin oxide (SnO2) nanowires with rutile structure have been synthesized by a facile hydrothermal method at 98 degrees C. The morphologies and structural properties of the as-grown nanowires/nanoneedles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction, X-ray diffracti...

Single-crystalline SnO2 microcubes were grown using the hydrothermal method without any catalyst. X-ray diffraction (XRD) patterns and energy dispersive X-ray (EDX) analysis verified that the cubes are tin dioxide SnO2. Their morphology and structure was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected...

We present here a study of methanol (MeOH) decomposition over a series of bimetallic Pt-M catalysts, with M=Au, Pd, Ru, Fe. All samples have the same initial size distribution (∼3nm nanoparticle height), support (ZrO2), and preparation conditions. Therefore, differences in the electronic and catalytic properties of the samples tested are related di...

We present a new method to synthesize ZnO nanorods on zinc spheres to form a core-shell structure. Selective self-assembly growth of a shell with ZnO nanorods on a metallic Zn microsphere core has been accomplished via hydrothermal synthesis. The crystal structure, morphologies and chemical composition were characterized by X-ray diffraction, trans...

ZnO nanorods and nanowires are promising candidates as new types of high-sensitivity ultraviolet (UV) photodetectors due to their wide bandgap and large aspect ratio. In this study, single-crystalline ZnO nanorods were grown on glass substrates by a hydrothermal method. Specific structural, morphological, electrical, and optical measurements were c...

Propagation of surface plasmons on gold in the range 2.8 – 3.5 eV over 0.1 – 1.6 μ m distances was characterized by cathodoluminescence spectroscopy. Surface plasmons were excited by an electron beam near a grating milled in the gold. The spectra of outcoupled radiation reveal increasingly strong propagation losses as surface plasmon energy increas...

We have investigated three-dimensional (3-D) architectures–microspheres and radial structures–based on biopolymer-assisted self-assembly from one-dimensional ZnO nanorods. The developed method is simple, rapid and cost-effective and can be used for self-assembly of different complex superstructures. A possible model of 3-D architectures self-assemb...

The thermally grown oxide (TGO) scale in thermal barrier coatings (TBCs) has been frequently associated with the durability and reliability of TBCs. In this study, the microstructure and phase constituents of the TGO scale were examined using transmission and scanning transmission electron microscopy (TEM/STEM). The TGO scales in several types of T...

Fourteen SiC-based materials were processed by hot pressing. The single-edge precracked beam (SEPB) fracture toughness varied from 2.4 to 6.8 MPa-m1/2 and fracture modes changed from transgranular to intergranular. Grain boundaries and triple points were analyzed using high-resolution transmission electron microscopy combined with energy dispersive...

Synthesis of thin (5−8 nm) CdS−Mn/ZnS core−shell nanowires (CSNWs) with high aspect ratio (up to 150) is reported for the first time. The modified solvothermal synthesis of CSNW involved two steps: the formation of Mn-doped CdS core followed by the ZnS shell. The CSNW growth process is engineered in such a way that the ZnS shell layer grew radially...

The study of nanomaterials is not only limited to the characterization of their properties as an ensemble of nanoparticles, but also often extends to the study of individual nanoparticles. Variations in size, shape and internal structure of nanoparticles may influence the macroscopic properties of these materials. Therefore, research in nanotechnol...

A facile aqueous solution process to fabricate tin oxide nanoarchitectures was successfully developed. The influence of precursors on the morphology of SnO2 is studied. Tin oxide nanobelts/nanoribbons were characterized by X-ray diffraction, micro-Raman spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Pos...

This paper presents an inexpensive and fast fabrication method for one-dimensional (1D) ZnO nanorod arrays and branched two-dimensional (2D), three-dimensional (3D) – nanoarchitectures. Our synthesis technique includes the use of an aqueous solution route and post-growth rapid thermal annealing. It permits rapid and controlled growth of ZnO nanorod...

We present here the decomposition of methanol over Pt nanoparticles supported on a series of oxide powders. The samples tested may be roughly grouped in two categories consisting of large (∼15–18nm) and small (∼8–9nm) Pt particles deposited on reducible (CeO2, TiO2) and non-reducible (SiO2, ZrO2, Al2O3) supports. The smallest particles (∼8nm), depo...

The structural and optical properties of erbium-doped silicon-rich silica samples containing 12 at. % of excess silicon and 0.63 at. % of erbium are studied as a function of annealing temperature in the range 600– 1200 ° C. Indirect excitation of Er 3+ ions is shown to be present for all annealing temperatures, including annealing temperatures well...

The authors report on the transport of energetic electrons through single, well aligned multiwall carbon nanotubes (CNTs). Embedding of CNTs in a protective carbon fiber coating enables the application of focused ion beam based sample preparation techniques for the nondestructive isolation and alignment of individual tubes. Aligned tubes with lengt...

The hollow structure of the carbon nanotube (CNT) provides a significant chance to use it for the channeling of charged particles and associated channeling radiation. However, the nano size of the CNTs make them difficult to be precisely controlled the position and the orientation. We successfully prepared a monolithic multiwall CNT with a graphiti...

Carbon nanostructures are synthesized using a novel arc-discharge in solution process. A multitude of defects on nanotubes and nanostructures is found. Evidence of these defects in as-synthesized carbon nanostructures is explored using high-resolution transmission electron microscopy (HRTEM). Tri-, tetra-, penta-, hexa-, heptagonal, toroidal, oval,...

A parametric study was carried out on a novel carbon nanotube (CNT) synthesis using 'arc-discharge in solution' (ADS). The carbon nanostructure yield as a function of time, the rate of erosion of the anode, and the rate of deposition of carbonaceous materials on the cathode electrode were investigated. Amperage dependent normalized kinetic paramete...

The late stages of precipitation in aluminum-rich Al-Ag alloys with silver contents from 3 at.% to 22 at.% were studied with transmission electron microscopy. Shapes, sizes, and arrangements of plates of the stable hexagonal Ag 2Al phase forming on {111} planes of the f.c.c. matrix were analysed. The high-angle annular dark-field contrast in scanni...

Mechanical twinning is an important deformation mechanism of the γ phase of lamellar two-phase TiAl/Ti3Al. The tips of deformation twins reaching γ/α2 interfaces induce high stresses in the α2 phase. With weak-beam imaging, a component of the resulting strain field can be evaluated quantitatively. If the α2 lamellae exceed a thickness of about 200...

In this paper, we report the growth of bamboo-like silicon-doped boron nitride nanotubes via catalyst-assisted pyrolysis of a boron-containing polymeric precursor. The morphologies and structures of the nanotubes were characterized using electron microscopy and Raman spectroscopy. Two types of nanotubes are observed, one from a base-growth mode and...

The phase transformation of mechanically milled nano-sized -alumina particles was investigated. The structures and phase presentation of the powders before and after milling were characterized using X-ray diffraction, transmission electron microscopy, and photoluminescence measurement. The phase transformation kinetics was investigated using differ...

The method of arc discharge in the solution is unique and inexpensive route for synthesis of the carbon nanotubes (CNTs), carbon onions, and other carbon nanostructures. Such a method can be used for in situ synthesis of CNTs decorated with nanoparticles. Herein, we report a simple and inexpensive optoelectronically automated system for arc dischar...

To characterize the influence of sodium diffusion on the Cu(In,Ga)Se 2 (CIGS) layer, samples with and without an A12O3 diffusion barrier were investigated by transmission electron microscopy. The soda lime glass acts as a sodium source for samples without diffusion barrier while a post deposition treatment with NaF adds sodium to the CIGS layer for...

A unique, simple, inexpensive, and one-step synthesis route to produce carbon nanotubes (CNTs) decorated with palladium nanoparticles using a simplified dc arc-discharge in solution is reported. Zero-loss energy filtered transmission electron microscopy and scanning transmission electron microscopy confirm the presence of 3 nm palladium nanoparticl...

A detailed description of the displacive transformation mode of the formation of plate-like τ-phase in MnAl (containing a small amount of carbon) is given. The plate-like τ-phase forms in a stepwise mode from the ε-phase. Crystallographic correspondence is transmitted from the ε- to the τ-phase during the whole transformation sequence. The intermed...

A unique, simple, inexpensive and one-step synthesis route of carbon nanotubes (CNT) supported palladium nanoparticles using a simplified arc-discharge in solution is reported. Palladium nanoparticles with 3 nm diameter were found to form during reduction of palladium tetra-chloro-square-planar complex. Pd-nanoparticles were simultaneously encapsul...

CdTe layers have been grown on CdS layers to produce thin-film photovoltaic devices. Because of the large lattice mismatch of roughly 10%, CdTe and CdS can only be joined at the expense of a high density of misfit dislocations. Additionally, after deposition the CdTe layer contains submicrometer sized, [111] oriented, columnar grains with a high de...