Crystal Phases in Hybrid Metal-Semiconductor Nanowire Devices.

David, J; Rossella, F; Rocci, M; Ercolani, D; Sorba, L; Beltram, F; Gemmi, M; Roddaro, S · Nano Lett · 2017

basic_science · Level V

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Abstract

We investigate the metallic phases observed in hybrid metal-GaAs nanowire devices obtained by controlled thermal annealing of Ni/Au electrodes. Devices are fabricated onto a SiN membrane compatible with transmission electron microscopy studies. Energy dispersive X-ray spectroscopy allows us to show that the nanowire body includes two Ni-rich phases that thanks to an innovative use of electron diffraction tomography can be unambiguously identified as Ni<sub>3</sub>GaAs and Ni<sub>5</sub>As<sub>2</sub> crystals. The mechanisms of Ni incorporation leading to the observed phenomenology are discussed.