J. F. Morhange

Raman study of laser annealed silicon

Abstract Raman spectroscopy of laser annealed implanted Silicon shows a phonon peak shifted up to ten cm-1 compared with a perfect crystalline sample. This shifted peak is interpreted as being due to the finite size of microcrystallites existing in the annealed region where the energy is below the fusion threshold. A simple model describing the vibrationnal properties of such crystallites has been established and compared to the experimental results.

Excitonic resonant second harmonic in GaSe

Abstract The resonant behaviour of second harmonic generation, in GaSe, has been observed, at room temperature, when the energy of the fondamental photon is close to the ground state of the first partially allowed exciton. The experiment has been carried out using a tunable, CW, dye laser. At resonance, a breakdown of the selection rules is observed.