Demonstration of near-field scanning photoreflectance spectroscopy

A near-field scanning optical microscope (NSOM) was developed to perform ph otoreflectance (PR) spectroscopy experiments at high spatial resolution (si milar to 1 mu m). Representative PR spectra are shown, along with an image illustrating the capability of observing contrast in images due to the stre ngth of a PR feature. It was found that sufficiently high intensity light f rom the NSOM tip can produce photovoltages large enough to limit the spatia l resolution of the electric field determination by PR. The photovoltage ef fect is measured as a function of light intensity, and the results are disc ussed in terms of a simple photovoltage expression. (C) 2000 American Insti tute of Physics. [S0003-6951(00)01839-8].