New mechanical constructions for the scanning tunneling microscope

Since the development of our first STM device, we designed several other versions for special applications and with less sensitivity to vibrations and temperature variations. The first device to be discussed is a new fine-positioning system for the tip. The features of this new device are a large stiffness combined with a low sensitivity to temperature drift due to a compensation principle in three directions. The coarse displacement is realised by moving the whole fine-positioning system towards and from or parallel to a fixed sample by means of two piezo-electric push-pull systems. Another possibility, for use in ambient air, is a fixed fine-positioning unit, on which a double leaf spring system is mounted that provides a displacement of the sample in two directions, one perpendicular and one parallel to the sample surface. Another fine-positioning system was developed to perform inelastic electron tunneling spectroscopy (IETS). Here the possibility of scanning a surface has been abandoned in order to get the very stable tunnel junction, necessary to do IETS.