SCANNING TUNNELING SPECTROSCOPY

The development of the field of spectroscopic measurement with the scanning tunneling microscope (STM) is discussed. A historical review of early experimental results in this field is presented, with emphasis on the techniques for data acquisition and interpretation. The applicability of STM spectroscopic measurement to surface structural determination is addressed. The role of geometric versus electronic contributions to STM images is discussed, with reference to studies of Si(111)7 x 7, Si(111)2 x 1, and Ge(111)c(2 x 8) surfaces. It is concluded that, for semiconductor surfaces, the observed corrugations are dominated by electronic effects. Issues of dynamic range in spectroscopic measurement, and interpretation of spectroscopic images, are examined.