Determination of the interband and the free carrier absorption constants in silicon at high-level photoinjection

Describes and experimental method together with an analysis of the experimental data, which makes it possible to determine the interband absorption coefficient, the free carrier absorption cross-section and the surface reflectivity in the same experimental set-up. The experiments were performed on samples of pure silicon at T=294K using a pulsed Nd-YAG laser, which gave pulses of 10-15 ns duration at lambda =1.06 mu m. The maximum carrier concentration achieved was about 3*10 19 cm -3 . Effects of laser beam inhomogeneities are also discussed and included in the absorption model.