Scanning localized viscoelastic image using a quartz crystal resonator combined with an atomic force microscopy

A quartz crystal resonator and an atomic force microscopy were applied for the measurement of local viscoelasticity and surface morphology. For the reduction of signal noise from the quartz crystal resonator, we designed an oscillation circuit based on a referential quartz crystal method. A polystyrene bead-coated quartz crystal was used as a signal quartz crystal, and a bare Au quartz crystal was used as a reference. By approaching the cantilever of atomic force microscopy to the surface of working quartz crystal, the differential resonant frequency in the two quartz crystals showed changes by the interaction between the tip and the quartz crystal. The changes of differential resonant frequency in the two quartz crystals were influenced by the local viscoelasticity. The image resolution of differential resonant frequency was observed under 80 nm for the polystyrene bead-coated quartz crystal. (C) 1999 American Institute of Physics. [S0003-6951(99)00803-7].