Bi2O3 nanowire growth from high-density Bi nanowires grown at a low temperature using aluminum–bismuth co-deposited films

Single crystalline Bi2O3 nanowires were prepared by annealing in oxygen ambient using pure Bi nanowires grown at a low vacuum (∼10−6 Torr) with Bi–Al co-sputtered films. The ability to grow Bi nanowires using Bi–Al co-sputtered films can be attributed to the suppression of the oxidation of the bismuth by the preferred oxidation of aluminum in co-sputtered ambient (∼mTorr). The Bi nanowires from the Bi–Al co-sputtered films could be grown even at the low temperature of 230 °C in low-vacuum ambient. The Bi2O3 nanowires prepared from the Bi nanowires showed a single crystalline structure with (1 1 1), ( 1 ¯     2     2 ) , (1 2 0), and (0 1 2) planes. The current–voltage (I–V) relationship of the Bi2O3 nanowire revealed that the Bi2O3 nanowire exhibited a semiconducting property with a resistivity of 14.6 Ω-cm. Variations in resistance of the Bi2O3 single nanowire as a function of time at 350 °C showed reproducible response and recovery time characteristics for each concentration of NO. The electric resistance of the Bi2O3 single nanowire was sensitive to NO gas even at 10 ppm.