Near-field Scanning Optical Microscopy — Breaking the diffraction limit using nano light emitting probe tip

We describe optical and topographic imaging using a light emitting diode (LED) monolithically integrated on a silicon probe tip for Near-field Scanning Optical Microscopy (NSOM). The light emission resulted from a silicon dioxide layer buried between a phosphorus-doped N+ silicon layer and a gallium-doped P+ silicon region created locally at the tip by a focused ion beam (FIB). The tip was employed in a standard NSOM excitation setup. The probe successfully measured optical as well as topographic images of a chromium test pattern with imaging resolutions of 400 nm and 50 nm, respectively. The directional resolution dependence of the acquired images directly corresponds to the shape, size and polarity of the light source on the probe tip. To our knowledge, this report is the first successful near-field imaging result directly measured by such tip-embedded light sources.