I–V curve oscillation observed by atomic force microscopy

Oscillation on the current–voltage curve measured by atomic force microscopy is observed when the distance between the tip and sample is large enough and beyond a critical value. The appearance of the oscillation is attributed to the excitation of electron standing waves between the tip and sample. From the first peak position and the voltage difference between the first two peaks on the current–voltage curve, the value of the work function at the detected point on silver film surface and the distance between the tip and the detected point can be calculated