1. Direct measurement of ambipolar diffusion in bulk silicon by ultrafast infrared imaging of laser-induced microplasmas.
- Author
-
Mouskeftaras, Alexandros, Chanal, Margaux, Chambonneau, Maxime, Clady, Raphaël, Utéza, Olivier, and Grojo, David
- Subjects
- *
CHARGE carriers , *SILICON crystals , *RECOMBINATION (Chemistry) , *FEMTOSECOND lasers , *LIGHT absorption , *INFRARED microscopy , *RATE equation model - Abstract
Carrier kinetics in the density range of N = 1017 - 1020 cm-3 is investigated inside the bulk of crystalline silicon. Most conventional experimental techniques used to study carrier mobility are indirect and lack sensitivity because of charging effects and recombination on the surface. An all optical technique is used to overcome these obstacles. By focusing 1.3-µm femtosecond laser pulses in the volume, we inject an initial free-carrier population by two-photon absorption. Then, we use pump-and-probe infrared microscopy as a tool to obtain simultaneous measurements of the carrier diffusion and recombination dynamics in a microscale region deep inside the material. The rate equation model is used to simulate our experimental results. We report a constant ambipolar diffusion coefficient Da of 2:5 cm² s-1 and an effective carrier lifetime τeff of 2:5 ns at room temperature. A discussion on our findings at these high-injection levels is presented. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF