Figure 2From: Potential sensitivities in frequency modulation and heterodyne amplitude modulation Kelvin probe force microscopesModulation signal spectrums of FM- and HAM-KPFM detected signals at a modulation amplitude of 150 mV (a,b). VDC = -100 mV, A = 6.5 nm, Δf = -20Hz, f1st = 165 KHz, f2nd =1.0089 MHz. fmod = 500 Hz for FM-KPFM.Back to article page