Page 195 - Science at the nanoscale

RPS: PSP0007 - Science-at-Nanoscale
10:16
June 5, 2009
8.3. Scanning Probe Microscopy
of Tip
of Sample
Barrier
Empty
Empty
States
States
Filled
Filled
States
States
(a)
Energy Levels
of Tip
Energy Levels
of Sample
Empty
Vacuum
States
Empty
Barrier
States
eV
Fermi Level
Filled
States
Filled
States
(b)
Energy Levels
of Sample
Energy Levels
of Tip
Vacuum
Empty
Barrier
States Energy Levels Vacuum Energy Levels Fermi Level 185 ch08
Fermi Level
eV
Filled
States
Filled
States
(c)
Figure 8.24. Energy band diagrams of the STM tip and the sample
(a) without any voltage bias, (b) when the tip is negatively biased with
respect to the sample, (c) when the tip is positively biased with respect to
the sample.