A Development of a High Resolution FM-AFM Working in Air or Solution

Abstract

Frequency modulation atomic force microscopy (FM-AFM) is a powerful method not only for imaging surfaces at the atomic scale but also for investigating surface properties. However, the high-resolution FM-AFM observations have been limited in vacuum environments where the Q-factor of the cantilever resonance usually exceeds 10,000. It is heavily reduced in air or liquids and hence the effective force sensitivity is decreased. We have developed a low noise cantilever deflection sensor by optimizing the optical design of the sensor and by modulating the laser power with a high frequency signal. Using this sensor, we have developed a high-resolution FM-AFM working in both air and liquids.