Near-field imaging of the photocurrent on Au/GaAs interface with various wavelengths

Abstract This contribution presents an application of scanning nearfield microscopy to the char-acterization of semiconductors. We have studied the planar homogeneity of a Au/GaAs Schottky barrier using a local illumination by a nanosource with various wavelengths.One of the main results is the interface defaults revealed by the photocurrent mapping at ) = 1.33im. 1. Introduction As the technology of semi-conductors uses structures of subwavelength dimension, the Scanning Near Field Optical Microscope (SNOM) appears as a powerful mean of investigation to controltheir real working mode and to detect inhomogeneities. Spectacular results were obtained withlocal spectroscopy of quantum structures,' field mapping in guiding structures2'3 and in lasercavities, mapping of the induced photocurrent... In this last application, which is an extensionof far field methods OBIC (optical beam induced current),4 the focused laser beam is replacedby a nanosource. The authors stress on the vertical analysis of the layers5 or on the lateral