We previously demonstrated that TiOx/Al2O3 nanolaminates (TAO NL) exhibit abnormally high-dielectric constant k (800–1000), due to Maxwell–Wagner polarization, via charge accumulation at insulating Al2O3/semiconducting TiOx interfaces. Here, we report TAO NL dielectric properties related to TiOx phase change in TiOx (0.9 nm)/Al2O3 (0.1 nm) NL. High-resolution transmission electron microscopy shows amorphous TiOx phase change to crystalline anatase TiO2 due to free-energy minimization. The phase change induce reduction in leakage current and dielectric loss (J = 10−2 to 10−4 A/cm2, tan δ = 10 to 10−1), still with k ~ 600 up to MHz, compared to amorphous TAO NLs.

Significant α-phase growth confinement in Grade 4 titanium (Ti) and substantial β-phase refinement in Grade 7 Ti were observed during high-temperature annealing. The mechanism for each observation was identified through detailed microstructural investigation assisted with phase diagram analyses. The former observation was due to the pinning effect of Fe-stabilized grain boundary (GB) β-Ti phases in Grade 4 Ti. The latter observation resulted from the redistribution of Fe and, palladium (Pd) in particular, in Fe-stabilized and Pd-containing GB β-Ti phases in Grade 7 Ti. Pd was found to exist mainly in two forms in cold-rolled Grade 7 Ti, i.e. Fe-stabilized GB β-Ti phases and an occasionally observed orthorhombic Ti88Pd9Fe3 phase. The latter is close to the Ti2Pd3 intermetallic phase in terms of the crystal structure.

Electrochemical dissolution by congruent oxidation of Fe Pd in 1 M HCl solution was strongly controlled by crystallographic orientation. Anodic dissolution was characterized over a wide variety of grain surface plane orientations providing a detailed view of the crystallographic nature of oxidative dissolution and surface facet evolution as a function of grain orientation. Near {100}-oriented grains retained low surface roughness after corrosion and low dissolution rates. Grains with orientation within 2° of {111} were also topographically smooth after dissolution and were nearly as corrosion resistant as {100} grains. Overall dissolution depth depended linearly on crystallographic angle within 40° of {100} and within 10° of {111} planes. Post-corrosion surface faceting and dissolution were substantially increased at grain orientations near {110} and were highest between 10° and 20° from the {111} plane normal. Grains at these crystallographic angles roughened during oxidative dissolution by forming complex semi-periodic topographies. These finely spaced arrays of terraces and ledges likely consisted of combinations of more corrosion resistant low-index planes. Therefore, the overall corrosion depth within a grain possessing an initially irrational crystal orientation was determined by the amount of dissolution required to expose new, slowly dissolving surface facets with low-index orientations. Computations of Fe–Pd alloy surface energies and surface atom coordination as a function of crystal orientation are utilized to help support this explanation.

Titanium oxide (TiO2) nanoparticles (NPs) were doped with vanadium using a novel, facile, and inexpensive method. The TiO2 NPs were dispersed in a vanadyl oxalate solution prepared by dissolving vanadium pentoxide (V2O5) in oxalic acid. A short heat treatment at 400 °C applied to the dried mixture resulted in the doping of TiO2 with a net measured decrease of its band gap by about 0.5 eV, making this important semiconductor material usable in the visible light spectrum.

Bacillus pasteurii was used as synthesis director for the formation of hollow cylinder and helical NiO micro/nanostructure under urea hydrolysis conditions. Bacteria were capable of precipitating nickel product from nickel solution by metabolic processes. An appropriate amount of both water and bacterial solution were required to precipitate the nickel product in good yield. The average crystallite size of NiO was 11.45 nm and lengths of the cylinder and helices were non-uniform (~2–7 µm) and were varied with bacterial body structure template. The present study demonstrates a feasibility of synthesizing bacteria-guided metal oxide crystals for various functional applications.

Interfacing organic electrochemical transistors (OECTs) with biological systems holds considerable promise for building-sensitive biosensors and diagnostic tools. We present a simple model that describes the performance of biosensors in which an OECT is integrated with a biological barrier layer. Using experimentally derived parameters we explore the limits of sensitivity and find that it is dependent on the resistance of the barrier layer. This work provides guidelines on how to optimize biosensors in which OECTs transduce changes in the impedance of biological layers, including lipid bilayer membranes and confluent cell layers.

A simple method was used to electrodeposit a metallic coating on vertically aligned carbon nanotube (CNT) arrays, herein referred to as turfs, creating an open cell, core–shell foam. The foam exhibited highly elastic behavior, approaching the amount of elastic recovery in compression of a pure CNT turf. The turfs were pre-treated with an acid bath, and were electroplated at low voltages with nickel and copper. This simple method can be expanded to prepare a large variety of nanostructured foams (e.g., the carbon support can be changed, the metal deposited selected and its thickness controlled) while maintaining their mechanical robustness.

Compression loading on CrN/Cu/Si(100) micropillars containing 45°-inclined interfaces yielded unequivocal evidence of shear plastic flow within Cu thin films confined between non-deforming Si and CrN. Confined shear plastic flow occurred over Cu thicknesses between ~100 and 1200 nm, with a monotonically increasing flow stress as the thickness decreases. The demonstration of a significant dependence of the shear flow stress on the confined Cu film thickness offers a new example of scale-dependent plasticity, and a new experimental test case for non-local plasticity theories.