The role of liquid ink transport in the direct placement of quantum dot emitters onto sub-micrometer antennas by dip-pen nanolithography

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.F.D. and J.W. contributed equally to this work. F.D. was supported by postdoctoral funding of the Center for Integrated Nanotechnologies (CINT), an Office of Science (OS) Nanoscale Science Research Center (NSRC) and User Facility operated for the U.S. Department of Energy (DOE) by Los Alamos National Laboratory (LANL; Contract No. DE-AC52-06NA25396) and Sandia National Laboratories (Contract No. DE-NA-0003525), and the work was performed in large part at CINT and contributed to CINT User Project, C2013B0048. J.W., P.A.S., S.M., M.T., and J.A.H. acknowledge LANL Directed Research and Development Funds. C.J.S. is a CINT-funded technical specialist. M.R.B. was funded by an LANL Director's Postdoctoral Fellowship, and A.M.D. by a Single Investigator Small Group Research Grant (2009LANL1096), Division of Materials Science and Engineering (MSE), Office of Basic Energy Sciences (OBES), OS, DOE. Los Alamos National Laboratory, an affirmative action equal opportunity employer, is operated by Los Alamos National Security, LLC, for the National Nuclear Security Administration of the DOE under Contract No. DE-AC52-06NA25396. (Center for Integrated Nanotechnologies (CINT), an Office of Science (OS) Nanoscale Science Research Center (NSRC); DE-AC52-06NA25396 - U.S. Department of Energy (DOE); DE-NA-0003525 - U.S. Department of Energy (DOE); C2013B0048 - CINT User Project; LANL Directed Research and Development Funds; CINT; LANL Director's Postdoctoral Fellowship; 2009LANL1096 - Single Investigator Small Group Research Grant, Division of Materials Science and Engineering (MSE), Office of Basic Energy Sciences (OBES), OS, DOE; DE-AC52-06NA25396 - National Nuclear Security Administration of the DOE)Accepted manuscrip

The Role of Liquid Ink Transport in the Direct Placement of Quantum Dot Emitters onto Sub-Micrometer Antennas by Dip-Pen Nanolithography

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.F.D. was supported by postdoctoral funding of the Center for Integrated Nanotechnologies (CINT), an Office of Science (OS) Nanoscale Science Research Center (NSRC) and User Facility operated for the U.S. Department of Energy (DOE) by Los Alamos National Laboratory (LANL; Contract No. DE-AC52-06NA25396) and Sandia National Laboratories (Contract No. DE-NA-0003525), and the work was performed in large part at CINT and contributed to CINT User Project, C2013B0048. J.W., P.A.S., S.M., M.T., and J.A.H. acknowledge LANL Directed Research and Development Funds. C.J.S. is a CINT-funded technical specialist. M.R.B. was funded by an LANL Director’s Postdoctoral Fellowship, and A.M.D. by a Single Investigator Small Group Research Grant (2009LANL1096), Division of Materials Science and Engineering (MSE), Office of Basic Energy Sciences (OBES), OS, DOE. Los Alamos National Laboratory, an affirmative action equal opportunity employer, is operated by Los Alamos National Security, LLC, for the National Nuclear Security Administration of the DOE under Contract No. DE-AC52-06NA2539

Precision additive nanofabrication: the role of liquid ink transport in the direct placement of quantum dot emitters onto sub-micrometer antennas by dip-pen nanolithography (Small 31/2018)

Back cover graphic.In article number 1801503 , Jennifer A. Hollingsworth and co‐workers demonstrate an advance in nanofabrication using dip‐pen nanolithography (DPN) to directly place nanocrystal quantum dots onto a three‐dimensional nanostructured optical antenna. The results lay the groundwork for the expanded use of DPN and other scanning probe technologies for the additive preparation of functional multi‐component systems and devices at the nanoscale.Published versio