1/f noise in nanowires

We have measured the low-frequency resistance fluctuations (1 mHz<f<10 Hz) in Ag nanowires of diameter 15 nm<d<200 nm at room temperatures. The power spectral density (PSD) of the fluctuations has a 1/f^{\alpha} character as seen in metallic films and wires of larger dimension. Additionally, the PSD has a significant low-frequency component and the value of \alpha increases from the usual 1 to ~3/2 as the diameter d is reduced. The value of the normalized fluctuation \frac{<\Delta R^2>}{R^2} also increases as the diameter d is reduced. We observe that there are new features in the 1/f noise as the size of the wire is reduced and they become more prominent as the diameter of the wires approaches 15nm. It is important to investigate the origin of the new behavior as 1/f noise may become a limiting factor in the use of metal wires of nanometer dimensions as interconnects.