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Atomic-scale electric capacitive change detected with a charge amplifier installed in a non-contact atomic force microscope

Nanoscale surface analysis was performed by installing a charge amplifier (CA) in a non-contact atomic force microscopy system. Atomic-scale capacitance and contact potential difference (CPD) between the tip and a Si(111)-7 × 7 surface were examined. Topographic images were simultaneously observed with the CA channel images, which showed the atomic contrast. The contrast was ascribed to the product of the CPD variation with the capacitance. The CA channel was used to evaluate the capacitance. CA channel mapping could be complementary to Kelvin probe force microscopy and can provide fast scanning owing to the wide bandwidth of the CA.