II. EXPERIMENTAL DETAILS A. Synthesis of Ag NWsSynthesis of Ag NWs has been carried out by various procedures, such as template based 14,15 and soft solution methods. 16,17 Here, the Ag NWs were synthesized by reducing silver nitrate (AgNO 3 ) with ethylene glycol (EG) in presence of copper dichloride dihydrate (CuCl 2 + 2 H 2 O) and polyvinylpyrrolidone (PVP). The EG is used as solvent and reducing agent whereas the PVP is used as capping agent. 18 In the beginning, 10 mL of EG (Sigma-Aldrich, anhydrous 99.8 %) was heated in an oil bath at 151.5 ○ C for 1 h under continuous magnetic stirring at 260 rpm. Then, 80 µL of a 4 mM CuCl 2 + 2 H 2 O (Sigma-Aldrich, 99.999 %)/EG solution was added to the preheated EG and stirred for another 15 min. Next, 3 mL of 0.282 mM PVP (Sigma-arXiv:1410

Abstract. For β-Ga 2 O 3 only little information exist concerning the thermal properties, especially the thermal conductivity λ. Here, the thermal conductivity is measured by applying the electrical 3ω-method on Czochralski-grown β-Ga 2 O 3 bulk crystals, which have a thickness of 200 µm and 800 µm. At room temperature the thermal conductivity along the [100]-direction in Mg-doped electrical insulating and undoped semiconducting β-Ga 2 O 3 is confirmed as 13 ± 1 Wm −1 K −1 for both crystals. The thermal conductivity increases for decreasing temperature down to 25 K to λ(25 K) = (5.3±0.6)·102 Wm −1 K −1 . The phonon contribution of λ dominates over the electron contribution below room temperature. The observed function λ(T ) is in accord with phonon-phonon-Umklapp scattering and the Debye-model for the specific heat at T 90 K which is about 0

The influence of size effects on the thermoelectric properties of thin platinum films is investigated and compared to the bulk. Structural properties, like the film thickness and the grain size, are varied. We correlate the electron mean free path with the temperature dependence of the electrical conductivity and the absolute Seebeck coefficient SPt of platinum. A measurement platform was developed as a standardized method to determine SPt and show that SPt,film is reduced compared to SPt,bulk. Boundary and surface scattering reduce the thermodiffusion and the phonon drag contribution to SPt,film by nearly the same factor. We discuss in detail on behalf of a model, which describes the temperature dependence of the absolute Seebeck coefficient, the influence of size effects of electron-phonon and phonon-phonon interaction on SPt.

Bi 2 Sr 2-x La x CuO 6+δ and Bi 2-y Pb y Sr 2-x La x CuO 6+δ high-T c superconductors in a wide doping range from overdoped to heavily underdoped were studied by x-ray absorption and photoemission spectroscopy. The hole concentration p was determined by an analysis of the Cu L 3 -absorption edge. Besides the occupied density of states derived from photoemission, the unoccupied density of states was determined from the prepeak of the O K-absorption edge. Both, the occupied as well as the unoccupied density of states reveal the same dependence on hole doping, i.e. a continuous increase with increasing doping in the hole underdoped region and a constant density in the hole overdoped region. By comparing these results of single-layer BSLCO with previous results on single-layer LSCO it could be argued that besides the localized holes on Cu sites the CuO 2 -planes consist of two types of doped holes, from which the so-called mobile holes determine the intensity of the prepeak of the O 1s absorption edge

Short AbstractThe reduction of the thermal conductivity induced by nano-patterning is one of the major approaches for tailoring thermoelectric material properties. Here, we chose two individual bismuth telluride nanowires (NWs), one with a strong diameter variation (NW1) and the other with smooth sidewalls (NW2). We investigated the role of the diameter variation by means of a combined fullthermoelectrical, structural and chemical characterisation on single nanowires. The electrical conductivity of both NWs exceeds the bulk value indicating the presence of a topological surface state. The thermal conductivity of NW2 compares to the bulk, while NW1 is about half that of NW2.Above. HRTEM micrograph of the smooth NW side and the amorphous shell of varying thickness of about (5 ± 1) nm. The inset shows a power spectrum of the NW core.