The increasing scientific interest in crystalline nanowires and nanorods has stimulated their functional exploitation, and single-crystalline nanowires are nowadays emerging as building blocks for a new generation of electronic [1,2,3], and optoelectronic nanometer-scaled devices [4,5]. The structural and functional properties of nanostructures of ionic metal oxides are attracting almost the same consideration addressed to nanowires of silicon or group III–V compounds.