AN ELECTRET MICROPHONE AS A FORCE SENSOR FOR COMBINED SCANNING PROBE MICROSCOPY

The operation of an electret microphone as a sensitive force sensor in scanning probe microscopy is described. The behavior of the electret microphone used as a capacitive force sensor is characterized and the experimental setup for a combined STM/SFM is described. First applicat ions of this hybrid microscope to biological objects are presented. Un like in conventional force microscopy, the sample can be placed on the top of the force sensor. This allows for a free choice of the near-fi eld probe. Hence, the electret microphone is well suited for combined scanning microscopies where the probe-re-sample distance is kept const ant by force gradient measurement while the near-field probe measures some local properties of the specimen.