Abstract

Photocurrent measurement with near-field excitation is a novel technique for the diagnostics of semiconductor photonic devices.[ 1,2] So far, nearfield scanning optical microscope has been employed for the spatially-resolved observation of small structures on the surface or optically thin materials. In the study of bulk devices, however, their internal optical and transport properties should also be precisely examined. As a new technique, we propose a multi-wavelength near-field photocurrent measurement, applying to a lateral p- n junction. By systematically varying to the optical penetration depth from smaller than aperture diameter to the order of wavelength, we obtain “tomographic” information of the investigated material. Using this method, the orientation of p-n slanted interface is quantitatively determined for the first time.

© 1996 Optical Society of America