Lateral Resolution and Signal to Noise Ratio in Electrostatic Force Detection Based on Scanning Probe Microscopy

The Lateral resolution (LR) and signal-to-noise ratio (SNR) are the essential factors in the applications of scanning probe microscopy in quantitative measurement of surface charge distribution,potential profile,and dielectric properties.We use a model system to comprise Au nanoparticles (NPs) embedded in a polystyrene (PS) matrix to study the effects of various experimental parameters,such as modulation bias voltage,tip-sample distance,and actual tip shape,on the electrostatic interactions between the tips and samples.The results show that LR and SNR decrease when the tip-sample distance increases,while SNR increases with tip modulation voltage.LR is less sensitive to tip modulation voltage,but shows complex dependence on the sample geometric structure.In combination with a numerical simulation based on the integral capacitance model,the electrostatic force interaction between tip and sample was quantitatively analyzed.