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The Role of Liquid Ink Transport in the Direct Placement of Quantum Dot Emitters onto Sub‐Micrometer Antennas by Dip‐Pen Nanolithography
Author(s) -
Dawood Farah,
Wang Jun,
Schulze Peter A.,
Sheehan Chris J.,
Buck Matthew R.,
Dennis Allison M.,
Majumder Somak,
Krishnamurthy Sachi,
Ticknor Matthew,
Staude Isabelle,
Brener Igal,
Goodwin Peter M.,
Amro Nabil A.,
Hollingsworth Jennifer A.
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201801503
Subject(s) - nanolithography , dip pen nanolithography , quantum dot , materials science , nanotechnology , fabrication , substrate (aquarium) , nanocrystal , nanosphere lithography , inkwell , lithography , optoelectronics , nanostructure , micrometer , optics , composite material , medicine , oceanography , alternative medicine , pathology , geology , physics
Dip‐pen nanolithography (DPN) is used to precisely position core/thick‐shell (“giant”) quantum dots (gQDs; ≥10 nm in diameter) exclusively on top of silicon nanodisk antennas (≈500 nm diameter pillars with a height of ≈200 nm), resulting in periodic arrays of hybrid nanostructures and demonstrating a facile integration strategy toward next‐generation quantum light sources. A three‐step reading‐inking‐writing approach is employed, where atomic force microscopy (AFM) images of the pre‐patterned substrate topography are used as maps to direct accurate placement of nanocrystals. The DPN “ink” comprises gQDs suspended in a non‐aqueous carrier solvent, o ‐dichlorobenzene. Systematic analyses of factors influencing deposition rate for this non‐conventional DPN ink are described for flat substrates and used to establish the conditions required to achieve small (sub‐500 nm) feature sizes, namely: dwell time, ink‐substrate contact angle and ink volume. Finally, it is shown that the rate of solvent transport controls the feature size in which gQDs are found on the substrate, but also that the number and consistency of nanocrystals deposited depends on the stability of the gQD suspension. Overall, the results lay the groundwork for expanded use of nanocrystal liquid inks and DPN for fabrication of multi‐component nanostructures that are challenging to create using traditional lithographic techniques.