Fabrication and Characterization of Coaxial p-Copper Oxide/n-ZnO Nanowire Photodiodes

The deposition of copper oxide onto vertically well-aligned n-ZnO nanowires by sputtering and the fabrication of p-copper oxide/n-ZnO coaxial nanowire photodiodes are reported. It was found that we could change the copper oxidation number to obtain Cu 2 O/ZnO nanowire photodiode, Cu 4 O 3 /ZnO nanowire photodiode and CuO/ZnO nanowire photodiode by simply changing the O flow rate during deposition. It was also found that noise equivalent powers were 6.1 × 10 -11 , 3.8 × 10 -10 , and 7.2 × 10 -8 W while normalized detectivities were 6.35 × 10 9 , 1.02 × 10 9 , and 5.37 × 10 6 cmHz 0.5 W -1 for the fabricated Cu 2 O/ZnO nanowire photodiode, Cu 4 O 3 /ZnO nanowire photodiode and CuO/ZnO nanowire photodiode, respectively.