We used optical pumping by the Vanderbilt free-electron laser (FEL) an
d the technique of internal photoemission (IPE) to measure with an acc
uracy of nearly 5 meV the conduction-band discontinuity of semiconduct
or heterojunction interfaces as GaAlAs-GaAs and Ge-GaAs. Very recently
we demonstrated, using a titanium-sapphire pumped laser, that spatial
ly resolved internal photoemission measurements could be performed on
a Pt/n-GaP Schottky barrier by a scanning near-field optics microscope
within a spatial resolution of 100 nm. Shear-force and photocurrent X
-Y images at different photon energies enable us to map the topography
and the Schottky barrier height on the same surface. The topography's
images, compared with the internal photoemission images, revealed zon
es where the morphology of the metallic layer was homogeneous, whereas
the photocurrent was varying from place to place. Both results opened
the possibility of measuring, in a simple and direct way, the local i
nterface properties of real devices. A novel technique with submicrome
tric spatial resolution could be implemented: the spatially analyzed F
EL-IPE (SAN FEL-IPE).