Single monolayer nanocrystal LED on probe tip for near-field molecular imaging and patterning

We report a novel light emitting nano-diode structure consisting of a single monolayer of CdSe nanocrystals deposited on a scanning probe tip for near-field scanning optical microscopy (NSOM). P-doped silicon which forms the probe body was utilized as an anode of the LED. A Langmuir-Blodgett (LB) trough was used to deposit on-probe a monolayer of nanocrystals (5-10 nm thickness), which were then examined with a SEM/TEM to show uniform deposition, and a fluorescent microscope to demonstrate light emitting properties. Both photoluminescent and electroluminescent emissions were observed from the fabricated probe with monolayer LED. Preliminary imaging and patterning using functional light emitting silicon probes were demonstrated in a standard NSOM setup. Resolutions of 50 nm and 400 nm were acquired for topographic and optical imaging, respectively.