Electrical and Structural Characterization of Germanium Nanowires

Germanium nanowires were grown by thermal evaporation of germanium powder associated with the well known vapor-liquid-solid mechanism (VLS). The nanowires were investigated by x-ray diffraction (XRD), Raman spectroscopy and field emission gun scanning electron microscopy (FEG-SEM). Through the fabrication of a germanium nanowires-based device we have studied the electronic transport properties of these samples. The transport measurements revealed semiconductor – like features, characterized by the decrease of the resistance as the temperature decreases. The variable range hopping (VRH) was identified as the main transport mechanism in a large temperature range (77 K < T < 400 K) thus giving consistent support to the mechanisms underlying the observed semiconducting character.