Interaction of scanning probes with semiconductor nanocrystals; physical mechanism and basis for near-field optical imaging

Yuval Ebenstein, Eyal Yoskovitz, Ronny Costi, Assaf Aharoni, Uri Banin

Research output: Contribution to journalArticlepeer-review

Abstract

We investigate the modification of photoluminescence (PL) from single semiconductor nanocrystal quantum dots (NCs) in the proximity of metal and semiconducting atomic force microscope (AFM) tips. The presence of the tip alters the radiative decay rate of an emitter via interference and opens efficient nonradiative decay channels via energy transfer to the tip material. These effects cause quenching (or enhancement) of the emitter's PL intensity as a function of its distance from the interacting tip. We take advantage of this highly distance-dependent effect to realize a contrast mechanism for high-resolution optical imaging. AFM tips are optimized as energy acceptors by chemical functionalization with InAs NCs to achieve optical resolution down to 30 nm. The presented experimental scheme offers high-resolution optical information while maintaining the benefits of traditional AFM imaging. We directly measure the PL intensity of single NCs as a function of the tip distance. Our results are in good agreement with calculations made by a classical theoretical model describing an oscillating dipole interacting with a planar mirror.

Original languageEnglish
Pages (from-to)8297-8303
Number of pages7
JournalJournal of Physical Chemistry A
Volume110
Issue number27
DOIs
StatePublished - 13 Jul 2006
Externally publishedYes

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