ATOMIC SPECIES IDENTIFICATION IN STM USING AN IMAGING ATOM-PROBE TECHNIQUE

In this paper we report new experimental results with the scanning tun neling atom probe (STAP), a new instrument that combines the functions of a scanning tunneling microscope (STM) and a time-of-flight atom pr obe. In STM-mode, clusters of atoms are transferred from regions of in terest to the tip, from which they are ejected into a time-of-flight s pectrometer for species identification. Improvements to the instrument and experimental results with in situ grown germanium layers on Si(11 1)-(7 x 7) are shown. Problems with the atom transfer and possible rem edies are discussed. (C) 1998 Elsevier Science B.V.