A Raman spectrometer was used to probe the structure and luminescence of a range of europium-doped zirconia phosphors prepared by different routes. We have demonstrated that the synthesis method and precursor type have a strong influence on the structure and luminescence of the final phosphor product. Raman spectroscopy has also demonstrated the presence of local order around the dopant ions that is not apparent in x-ray diffraction (XRD) and corresponds with changes in luminescence. As europium concentration is increased from 1 mol% to 20 mol%, the long range structure (from XRD) changes from tetragonal to cubic. Raman spectroscopy, however, shows that the 1 mol% material has a localized structure similar to the monoclinic undoped zirconia. This localized symmetry can explain the differences observed previously in emission spectra.

Organic light-emitting devices (OLEDs) have been widely developed for flat-panel displays, but only recently the efficiency of white OLEDs has risen to the point where they can be considered for solid-state lighting (SSL) applications. In this review, we discuss the requirements of solid-state lighting as they relate to OLEDs. We focus on how the color, efficiency, and cost requirements of general illumination differ from those of displays and how these differences might have an impact on the design of organic SSL. We then present some recent developments in large-area fabrication techniques that might be appropriate for solid-state lighting applications. Finally, we review recent results in the development of organic materials, device architectures, light extraction schemes, and fabrication techniques that can lead to cost-effective OLED lighting.

Organic field-effect transistors (FETs) are currently the focus of significant academic research and industrial development interest, as they potentially offer unique advantages over their inorganic counterparts in terms of cost reductions, compatibility with low-temperature and printing-based manufacturing, and potentially even performance. The first generation of products incorporating organic FETs is presently being introduced to the market. This article provides an overview of strategies for achieving high field-effect mobilities in solution-processed organic semiconductor films. We provide an assessment of materials challenges to meet performance and reliability requirements for a range of display and circuit applications and present an overview of state-of-the-art application demonstrations in active-matrix addressing of flexible eletrophoretic, organic light-emitting diode, and liquid-crystal displays, as well as radio-frequency identification tagging. We discuss how the unique functional properties of organic semiconductors, which allow comparatively easy integration of information processing, information storage, light emission, and light detection functions, might enable multifunctional applications that are not easy to create with other material systems.

In this study, we synthesized Cu–Zr binary alloys reinforced with an ultrafine eutectic microstructure. The alloys consisted of alternating layers of a hard superlattice phase and a ductile Cu phase with a very fine interlamellar spacing of ∼60 nm. The superlattice phase enhanced the strength of the alloys while the laminated composite structure helped improve their plasticity, making their mechanical properties comparable to those of the earlier reported high strength alloys. This paper discusses the fundamental microstructural aspects that influence the mechanical properties of these alloys.

The effect of minor addition (MA) of metallic alloying elements in Cu–Ti-rich Cu–Ti–Zr–Ni–Si bulk metallic glasses (BMGs) has been investigated. MA of elements having a relatively small positive enthalpy of mixing (partial substitution of Zr with Nb) leads to enhancement of compressive plasticity (up to about 5% of fracture strain) when the addition leads to improvement in glass-forming ability (GFA). If the GFA is reduced (partial substitution of Ni with Ag or Co), the plasticity is also reduced. On the one hand, the MA of elements having a relatively large positive enthalpy of mixing (partial substitution of Zr with Y) can lead to the liquid-state phase separation in Cu–Ti–Zr–Ni–Si(–Sn) BMGs, although the addition can lead to drastic deterioration in GFA and plasticity. This concept would be considered to be effective even in design of other BMG systems with tailored properties.

Grain growth in 40-nm-thick Cu films encapsulated by over- and under-layers of SiO2, Al2O3, Si3N4, and MgO was investigated. The films were magnetron sputter deposited onto cooled SiO2/Si substrates in an ultrahigh vacuum purity environment. Ex situ annealing was performed at 400 and 800 °C in 1 atm reducing gas. Films deposited at −120 °C exhibited more extensive grain growth after annealing than films deposited at −40 °C. Films annealed at room temperature had grain sizes less than 35 nm. All films exhibited some void formation after annealing at 400 and 800 °C, but the films encapsulated in Al2O3 exhibited the lowest area fraction of voids. The mean grain sizes of the Al2O3-encapsulated films, as measured by the linear intercept method, were 86 and 134 nm after annealing at 400 and 800 °C, respectively.

This is the second in a series of articles demonstrating the unique character of the aerosol-through-plasma (A-T-P) process for producing nanoparticles. This study is focused on the impact of two parameters, cation ratio (1:3, 1:1, 3:1) and solvent (evaporated prior to generation of aerosol), on the structures of Ce:Al oxides particles. These two simple changes were found to impact virtually every aspect of particle structure, including the fraction of hollow versus solid, fraction of nanoparticles, phase structure, and even the existence of surface phase segregation. CeAl mixed oxides were found only over a limited range of compositions, and that range was a function of the solvent. At all other cation ratios, only ceria was a crystalline phase, and most if not all the alumina is amorphous. It is notable that the fraction of hollow micron-sized particles and nanoparticles is greatly influenced by the cation ratio and solvent identity. Indeed, significant numbers of nanoparticles were only produced using an aqueous precursor with a Ce:Al ratio of 1:1. Another unique finding is that phase segregation exists in individual particles on the length scale of nanometers. This study compliments an earlier study of the influence of operating conditions on particle structure. Taken together, the studies suggest a means to engineer (as well as limits to the engineering possibilities) ceramic particle structures using the A-T-P method.

The field of organic electronics is entering its commercial phase. The recent market introduction of the first prototypes based on organic transistors fabricated from solution is set to augment the existing market presence of organic light-emitting diode applications. Organic photovoltaic products are not far behind. In this article, we provide a brief overview of these devices, with our main focus being organic transistor applications. In particular, we examine some of the key performance requirements for working devices. We also review some of the important advances in semiconductor design and device fabrication techniques and discuss some of the technical challenges that remain in the optimization of next-generation products.

We discuss some recent advances in the use of organic semiconductor devices with additional or enhanced functionality beyond simple electrical switching. These include diodes that act as local temperature sensors or that filter reverse-bias currents at tens of megahertz frequency. Transistors are described with a range of sensing and reporting functions, for such properties as pressure, magnetic field, and chemical vapor. Because these devices will likely be employed in arrays and assemblies, we also present concepts of some larger, integrated components such as artificial skin, sensor arrays, and wireless power systems. The common theme of these devices is that they build on an extensive and growing understanding of the parent transistors and diodes, but represent a departure into new physical phenomena and application areas.

In nanoindentation, the occurrence of cracks, pileup, sink-in, or film delamination adds additional complexity to the analysis of the load–displacement curves. Many techniques and analysis methods have been used to extract both qualitative and quantitative information from the indentation test both during and after the test. Much of this information is obtained indirectly or may even be overlooked by current testing methods (e.g., cracks that open only during the loading cycle of the test may go unnoticed from a typical residual indentation analysis). Here we report on the development of a miniature depth-sensing nanoindentation instrument and its integration into a high-resolution scanning electron microscope. Real-time observation of the nanoindentation test via scanning electron microscopy allows for visualization and detection of certain events such as crack initiation, pileup, or sink-in, and other material deformation phenomena. Initial results from aluminum 〈100〉 and a thin gold film (∼225 nm) are presented.

The deformation behavior of diamondlike carbon (DLC) coatings on silicon substrates induced by Berkovich indentation has been investigated. DLC coatings deposited by a plasma-assisted chemical vapor deposition technique were subjected to nanoindentation with a Berkovich indenter over a range of maximum loads from 100 to 300 mN. Distinct pop-ins were observed for loads greater than 150 mN. However, no pop-out was observed for the loads studied. The top surface of the indents showed annular cracks with associated fragmented material. The cross sections showed up to 20% localized reduction in thickness of the DLC coating beneath the indenter tip. Cracking, {111} slip, stacking faults, and localized phase transformations were observed in the silicon substrate. The discontinuities in the load–displacement curves at low loads are attributed to plastic deformation of the silicon substrate, whereas at higher loads they are attributed to plastic deformation as well as phase transformation.

The formation of bulk metallic glasses (BMGs) and their room temperature mechanical properties have been investigated in a serial of Ni65−xZr20Nb15Pdx (x = 0∼15; at.%) quaternary alloys, which are hopefully hydrogen-permeation materials. The partial substitution of Ni with Pd in Ni65Zr20Nb15 alloy has proved to be effective in improving glass-forming ability (GFA) and thermal stability. In particular, good BMG-forming compositions were revealed within the Pd content range of 2.5–12.5 at.%, and BMG rods of 3 mm in diameter were successfully made at compositions Ni57.5Zr20Nb15Pd7.5 and Ni55Zr20Nb15Pd10 by copper mold casting. The addition of Pd enhanced the thermal stability of the supercooled liquid. With an increase of Pd content, the supercooled liquid span, ΔTx = Tx − Tg, increased from 29 K at Ni65Zr20Nb15 to 47 K at Ni52.5Zr20Nb15Pd12.5. The Pd-bearing BMGs exhibited high fracture strength, which ranged from 2750 to 2850 MPa. These Pd-bearing BMGs showed a certain degree of toughness, and the highest plastic strain, about 2%, was reached in the Ni60Zr20Nb15Pd5 BMG.

This article discusses the importance of the choice of synthetic methodology in the purity, and therefore performance, of both small-molecule and polymeric organic semiconductors. We discuss common methodologies used in the preparation of organic semiconductors, paying particular attention to the impurities and by-products that can arise during these synthetic approaches and how they can have an impact on semiconductor performance.