J. Phys. III France
Volume 3, Numéro 7, July 1993
Page(s) 1291 - 1303
DOI: 10.1051/jp3:1993199
J. Phys. III France 3 (1993) 1291-1303

Picosecond investigation of photorefractive and free carrier gratings in GaAs: EL2 and CdTe: V

Philippe Delaye1, Kestutis Jarasiunas1, Jean-Claude Launay2 and Gérald Roosen1

1  Institut d'Optique Théorique et Appliquée, URA 14 CNRS, Centre Scientifique d'Orsay, B.P. 147, 91403 Orsay Cedex, France
2  Pôle de Recherche Aquitain pour les Matériaux dans l'Espace (PRAME), B.P. 11, 33165 Saint Médard en Jalles Cedex, France

(Received 30 November 1992, revised 18 January 1993, accepted 9 February 1993)

Laser induced picosecond transient gratings are used to study carrier transport via free carrier and photorefractive nonlinearities in serni-insulating undoped GaAs and vanadium doped CdTe crystals. Absorption and carrier generation mechanisms are investigated through the variation of grating strengths with input fluence. We show that grating decays are governed by mostly ambipolar diffusion and by its variation with fluence. Ambipolar mobilities are measured: $\mu_{\rm a}\approx 135$ cm $^2.{\rm V}^{-1}.{\rm s}^{-1}$ in CdTe and $\mu_{\rm a}\approx 760$ cm $^2.{\rm V}^{-1}.{\rm s}^{-1}$ in GaAs.

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