Laboratoire d'Optique P.M. Duffieux (UMR 6603 CNRS), Institut des Microtechniques (FR W0067 CNRS), UFR Sciences, 25030 Besançon Cedex, France
École Polytechnique Fédérale PH–Ecublens, 1015 Lausanne, Switzerland
CNR-ISM, via E. Fermi 38, 00044 Frascati Roma, Italy
L2M-CNRS, 196 avenue Henri Ravera, B.P. 107, 92225 Bagneux Cedex, France
INFN, Dipartimento di Fisica, Università di Roma "La Sapienza" P. le A. Moro, 00185 Roma, Italy
This contribution presents an application of scanning near-field optical microscopy to the characterization of semi-conductors. It is based on the photocurrent mapping of a patterned Au/GaAs structure (Schottky barrier) under local illumination by the nanosource. The results obtained with different wavelengths, metallized or dielectric probes and different bias voltages exhibit photocurrent variations independent of the topography and induced by interface defects. Finally, from this study of a patterned planar structure, we propose a method to determine the mean free path of the charge carriers in the volume.
(Received July 02 1998)
(Revised September 29 1998)
(Accepted November 13 1998)
(Online publication March 15 1999)
* This paper was presented at the special CFMCP colloquium held at Strasbourg-Illkirch the July 1st-3rd, 1998.