Near-field optical study of semiconductor photonic devices

A novel-structured semiconductor photonic device is investigated using a near-field scanning optical microscope. By tailoring the shape of the fiber probe, high transmission and collection efficiencies are successfully achieved. Employing optimized fiber tips, multi-diagnostics of lateral p-n junctions is performed with the AFM operation. Measuring the spatially resolved photoluminescence spectra, we precisely examine the carrier distribution in the transition region of the p-n junctions. Electroluminescence imaging reveals the width and the position of the active region. The slant angle of the p-n interface is determined by applying the multiwavelength near-field photocurrent measurement. We also clarify the mechanism of the mode conversion due to the interaction between the evanescent light on a small aperture and optically dense semiconductors.