G. Lee et al., VOLTAGE-DEPENDENT SCANNING-TUNNELING-MICROSCOPY IMAGES OF THE GE(111)-C(2X8) SURFACE, Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 16(3), 1998, pp. 1006-1009
Citations number
13
Categorie Soggetti
Physics, Applied","Materials Science, Coatings & Films
We present scanning tunneling microscopy images of the Ge(111)-c(2X8)
surface where both clean and impurity-containing portions exhibit sign
ificant voltage-dependent variations. While only adatoms are observed
in empty state images, both adatoms and rest atoms simultaneously appe
ar in filled state images but changing contrast with varying bias volt
age. The filled state image taken with a voltage as low as 0.5 V confi
rms that a surface state exists between rest-atom bands and the Fermi
level and it is not dangling-bond-like, i.e., its associated charge is
found to be distributed over both adatoms and rest atoms. The voltage
-dependent images of the impurity-containing surface show delocalized
features around the impurity. These delocalized features are observed
for the first time on the surface other than III-V semiconductor surfa
ces. It is attributed to the charged impurity relative to the clean pa
rt, causing the band bending near the impurity. (C) 1998 American Vacu
um Society.