Eur. Phys. J. AP 5, 283-288 (1999)
https://doi.org/10.1051/epjap:1999136

Near-field imaging of the photocurrent on a patterned Au/GaAs interface with various wavelengths and bias^*

¹ Laboratoire d'Optique P.M. Duffieux (UMR 6603 CNRS), Institut des Microtechniques (FR W0067 CNRS), UFR Sciences, 25030 Besançon Cedex, France
² École Polytechnique Fédérale PH–Ecublens, 1015 Lausanne, Switzerland
³ CNR-ISM, via E. Fermi 38, 00044 Frascati Roma, Italy
⁴ L2M-CNRS, 196 avenue Henri Ravera, B.P. 107, 92225 Bagneux Cedex, France
⁵ INFN, Dipartimento di Fisica, Università di Roma "La Sapienza" P. le A. Moro, 00185 Roma, Italy

Received: 2 July 1998
Revised: 29 September 1998
Accepted: 13 November 1998
Published online: 15 March 1999

Abstract

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.