Spatial Distribution of Photocurrent in Si Stripes under Tilted Illumination Measured by Multimode Scanning Probe Microscopy

摘要

Spatial distribution of photocurrent in Si stripes of 50-1000 nm in width were investigated as a function of optical excitation wavelength by multimode scanning probe microscopy (MSPM). Inhomogeneous distribution of the MSPM photocurrent in the Si stripe interior was attributed to the light intensity profile. A model that included light absorption depth profile and the probe-induced band-bending region reproduced the photocurrent profile for tilted illumination of the stripes. An effective spatial resolution of ～10nm was deduced from the photocurrent measurements with multimode SPM in the constant-force mode.