NANOMETER-SCALE CHEMICAL MODIFICATION USING A SCANNING TUNNELING MICROSCOPE

THE potential of the scanning tunnelling microscope (STM) as a tool for the high-resolution manipulation of surfaces and surface-adsorbed phases has been amply demonstrated1-5. In general, previous studies have been concerned with the physical rearrangement of surface atoms and molecules. Here I report the use of the STM to achieve chemical modification of a surface. An STM is used to etch the surface of a mixed-ionic conductor (AgxSe), producing selected patterns of grooves about 10 nm wide. The etching process seems to involve the segregation of different chemical species on the surface: silver atoms migrate into the semiconductor matrix that underlies the AgxSe film, exposing selenium ions which are then removed from the surface by reaction with ambient hydrogen. Chemical modification of this sort may come to play a part in future nanometre-scale technologies. © 1990 Nature Publishing Group.