Main field of study: 011200 Physics
Area of specialisation: Solid State Spectroscopy
Department of Solid State Physics
Scientific advisor: Doctor of Physical and Mathematical Sciences, Prof. V. P. Kochereshko
Reviewer: Doctor of Physical and Mathematical Sciences, Prof. V. F. Agekyan

Anomalous reflectivity spectra from epitaxial layers
V. V. Dubrovin

The objective of the work is to study the anomalies of the reflection spectra of crystals on the example of a semi-infinite crystal GaN, grown by molecular beam epitaxy. These abnormalities consist in the fact that reflectance near resonance at first decreases and then increases, increasing energy, and not vice versa as in a normal case. We explain this phenomenon with an influence of the near-surface region of the sample. The band bending at the surface leads to the appearance of space charge, which influences the exciton, leading to an exponential increase its damping toward the boundary of the crystal. This means the appearance of the dead, desexitoned layer due to the interference of light in which the above-mentioned deviations are observed. As a result of calculations using the model of the transition layer was obtained rotation of the reflection spectrum when changing the thickness of the transition layer. This clearly shows abnormal changes observed in the spectra.

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