The European Physical Journal Applied Physics

Table of Contents - March 1999 - Volume 5, Issue 03  

Research Article

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

S. Davya1, M. Spajera1, J. Almeidaa2, R. Generosia3, A. Cricentia3, G. Fainia4 and C. Coluzzaa5

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

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.

(Received July 02 1998)

(Revised September 29 1998)

(Accepted November 13 1998)

(Online publication March 15 1999)

PACS:

  • 07.79.Fc – Near-field scanning optical microscopes;
  • 61.72.Ji – Point defects (vacancies, interstitials, color centers, etc.) and defect clusters;
  • 79.60.-i – Photoemission and photoelectron spectra

Footnotes

*  This paper was presented at the special CFMCP colloquium held at Strasbourg-Illkirch the July 1st-3rd, 1998.