PHOTOEXCITED CARRIER DIFFUSION NEAR A SI(111) SURFACE - NON-NEGLIGIBLE CONSEQUENCE OF CARRIER-CARRIER SCATTERING

摘要

Photocarrier diffusion in Si at ambient temperature in the carrier density range of 4x10(17) to 4 x 10(19) cm(-3) has been characterized by the transient grating technique. Measurements show a strong density dependence in ambipolar diffusivity with a minimum of 4.7 cm(2) s(-1), a factor of 4 lower than the intrinsic value, at 10(19) cm(-3). The decrease is a result of carrier-carrier scattering at high densities. Measurements on both a Si(111) surface (reflection geometry) and a Si film (transmission geometry) indicate that there is no significant surface effect in diffusivity for carriers generated near the surface. [References: 25]