Growth and Characterization of Bismuth Telluride Nanowires

Polycrystalline Bi2Te3 nanowires are electrochemically grown in ion track-etched polycarbonate membranes. Potentiostatic growth is demonstrated in templates of various thicknesses ranging from 10 to 100 µm. The smallest observed nanowire diameters are 20 nm in thin membranes and approx. 140 -180 nm in thicker membranes. The influence of the various deposition parameters on the nanowire growth rate is presented. Slower growth rates are attained by selective change of deposition potentials and lower temperatures. Nanowires synthesized at slower growth rates have shown to possess a higher degree of crystalline order and smoother surface contours. With respect to structural properties, X-ray diffraction and transmission electron microscopy verified the growth of Bi2Te3 and evidenced the stability of specific properties, e.g. grain size or preferential orientation, with regard to variations in the deposition conditions. The interdependency of the fabrication parameters, i.e. temperature, deposition potential and nanochannel diameters, is demonstrated for wires grown in 30 µm thick membranes. It is visible from diffraction analysis that texture is tunable by the growth conditions but depends also on the size of the nanochannels in the template. Both (015) and (110) reflexes are observed for the nanowire arrays. Energy dispersive X-ray analysis further points out that variation of nanochannel size could lead to a change in elemental composition of the nanowires

Comments of the Max Planck Institute for Intellectual Property, Competition and Tax Law on the Draft Commission Block Exemption Regulation on Research and Development Agreements and the Draft Guidelines on Horizontal Cooperation Agreements

The paper represents the comments of the Max Planck Institute for Intellectual Property, Competition and Tax Law on the Draft Commission Regulation on the application of Art. 101(3) of the Treaty on the Functioning of the European Union to categories of research and development agreements and the Daft Guidelines on horizontal cooperation agreements. Given the particular expertise of the Institute both on intellectual property law and competition law, the comments focus on the Draft Research and Development (R&D) Block Exemption Regulation and Chapter 7 of the Draft Horizontal Guidelines dealing with standardisation agreements. The Institute does not comment on the Draft Block Exemption Regulation on Specialisation Agreements. The Institute is in support of the general approach of the Commission to revise the existing system. In particular, the Institute welcomes the clearer distinction between competition in the product market, the market for technology and finally competition for innovation. Yet, the following comments will concentrate on points where the Institute thinks that the current text may be improved. It is also held that clearer rules on how to deal with competition problems related to technological standards would be highly desirable. In this regard, the Institute is of the opinion that Chapter 7 of the Draft Horizontal Guidelines does not adequately respond to the challenges presented by technological standards

Electrochemical Synthesis of Bi1–xSbxNanowires with Simultaneous Control on Size, Composition, and Surface Roughness

We present the synthesis of Bi1–xSbx nanowires with controlled composition between x = 0.05 and x = 0.40 over a wide range of diameters (20–100 nm) interesting for the investigation of the enhancement of thermoelectric efficiency via quantum size effects. We find that the relative concentration of Bi and Sb ions in the electrolyte, together with the deposition potential, determines the resulting nanowire composition. Morphology and composition were analyzed using X-ray diffraction, electron microscopy, and energy dispersive X-ray analysis. Two different templates were fabricated to enable the synthesis of nanowires with smooth and rough contour

Tuning the Geometrical and Crystallographic Characteristics of Bi2Te3Bi_2Te_3 Nanowires by Electrodeposition in Ion-Track Membranes

We report the fabrication of Bi2Te3 nanowires with diameters as small as 15 nm, which is comparable to the size theoretically estimated for the onset of improvement of the thermoelectric figure of merit ZT by quantum-size effects. The versatility of the template-assisted growth, combining self-prepared ion-track etched membranes and electrochemical deposition, has been employed to synthesize Bi2Te3 nanowires with controlled diameters in 10, 30, and 60 µm thick membranes and with large aspect ratios (length over diameter) of up to 1000. SEM, HRTEM, and XRD investigations reveal how morphology, surface roughness, and crystalline orientation of the Bi2Te3 nanowires depend on deposition potential, temperature, and channel diameter

Highly-Ordered Supportless Three-Dimensional Nanowire Networks with Tunable Complexity and Interwire Connectivity for Device Integration

The fabrication of three-dimensional assemblies consisting of large quantities of nanowires is of great technological importance for various applications including (electro-)catalysis, sensitive sensing, and improvement of electronic devices. Because the spatial distribution of the nanostructured material can strongly influence the properties, architectural design is required in order to use assembled nanowires to their full potential. In addition, special effort has to be dedicated to the development of efficient methods that allow precise control over structural parameters of the nanoscale building blocks as a means of tuning their characteristics. This paper reports the direct synthesis of highly ordered large-area nanowire networks by a method based on hard templates using electrodeposition within nanochannels of ion track-etched polymer membranes. Control over the complexity of the networks and the dimensions of the integrated nanostructures are achieved by a modified template fabrication. The networks possess high surface area and excellent transport properties, turning them into a promising electrocatalyst material as demonstrated by cyclic voltammetry studies on platinum nanowire networks catalyzing methanol oxidation. Our method opens up a new general route for interconnecting nanowires to stable macroscopic network structures of very high integration level that allow easy handling of nanowires while maintaining their connectivity