Regensburg 2000 – scientific programme
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HL: Halbleiterphysik
HL 38: Poster III: Transporteigenschaften (1-14), Optische Eigenschaften (15-31), Grenz-/Oberfl
ächen (32-44), Heterostrukturen (45-57), Bauelemente (58-67), Gitterdynamik (68-69), Diamant (70), Raster-Tunnel-Mikroskopie (71)
HL 38.66: Poster
Thursday, March 30, 2000, 14:00–19:00, B
Imaging of submicrometer heat spots and subsurface thermal barriers by optically and electrically modulated photothermal microscopy — •D. Dietzel1, F. Niebiesch1, B.K. Bein1, J. Pelzl1, A.D. Wieck2, C. Crell3, and H. Röcken3 — 1Experimentalphysik III, Festkörperspektroskopie, Ruhr-Universität Bochum — 2Experimentalphysik VI, Angewandte Festkörperphysik, Ruhr-Universität Bochum — 3Experimentalphysik III, Ruhr-Universität Bochum
The heat spot and the surface and subsurface thermal barriers of
mesa devices have been investigated by means of a photothermal
microscope. The photothermal microscope built by our group offers
a lateral resolution of about 5 microns and relies on the optical
reflection of a He-Ne-laser probe beam by the sample which is
heated by means of a periodically modulated Ar-ion laser.
Subsurface insulating lines which had been generated by focussed
ion beams became visible when in addition a dc voltage was
applied. The inverse OBIC-effect increased linearly with the
applied voltage but did not change markedly with the modulation
frequency of the pump laser varied between 10kHz and 1MHz. The
contrast could be enhanced when the voltage was modulated and
the signal was recorded at multiples of the modulation
frequencies. The observations are explained on the basis of
changes of the reflectance due to induced charge carriers and
temperature effects.
(Work performed in the frame of the GRK 384)