A novel stress-induced method to grow semimetallic Bi nanowires along with an analysis of their transport properties is presented. Single crystalline Bi nanowires were found to grow on as-sputtered films after thermal annealing at 260-270 degrees C. This was facilitated by relaxation of stress between the film and the thermally oxidized Si substrate that originated from a mismatch of the thermal expansion. The diameter-tunable Bi nanowires can be produced by controlling the mean grain size of the film, which is dependent upon the thickness of the film. Four-terminal devices based on individual Bi nanowires were found to exhibit very large transverse and longitudinal ordinary magnetoresistance, indicating high-quality, single crystalline Bi nanowires. Unusual transport properties, including a mobility value of 76900 cm(2)/(V s) and a mean free path of 1.35 mum in a 120 nm Bi nanowire, were observed at room temperature.

We present the hydrogen sensing performance of individual Pd nanowires grown by electrodeposition into nanochannels of anodized aluminum oxide (AAO) templates investigated as a function of the nanowire diameter. Four-terminal devices based on individual Pd nanowires were found to successfully detect hydrogen gas (H(2)). Our experimental results show that the H(2) sensing sensitivity increases and the response time decreases with decreasing diameter of Pd nanowires with d = 400, 200, 80 and 20 nm, due to the high surface-to-volume ratio and short diffusion paths, respectively. This is in qualitatively good agreement with simulated results obtained from a theoretical model based on a combination of the rate equation and diffusion equation.

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The spin injection technique is extended to semimetal bismuth samples in a lateral spin valve geometry. We study spin injection, diffusion, and detection in a material system where a small change in sample stoichiometry results in a large change in the electronic and spin dependent transport properties of the nonmagnetic material. Measurements of magnetoresistance, using a magnetic field applied in the sample plane, as well as the Hanle effect, using a field applied perpendicular to the sample plane, are reported. We demonstrate two remarkable results: ͑i͒ a spin diffusion length of 230 m ͑T =2 K͒ in a BiPb sample with temperature dependent resistivity, ͑T͒, which decreases with decreasing T is the longest known value in a thin film; ͑ii͒ the interfacial spin polarization is 10% in BiPb samples with decreasing ͑T͒ and an order of magnitude smaller ͑0.8%͒ in Bi samples where ͑T͒ increases with decreasing T.