Dependence of Transport Rate on Area of Lithography and Pretreatment of Tip in Dip-Pen Nanolithography

Abstract

This study examines the lithographic capacity of tips in dip-pen nanolithography (DPN). The dependence of the transport rate (R) decay on the area of lithography (A(lith)), the dependence of A(lith) on the lithographic time (t), and the effect of piranha cleaning on the lithographic capacity are considered herein. The dependencies in the line-drawing lithography process are studied using 16-mercaptohexadecanoic acid (MHA) ink. On the basis of the linear decay dependence discovered in the R-A(lith) dependence, piranha treatment can increase the lithographic capacity by up to 35.5-fold, an improvement that may originate from a change in the tip's surface chemistry. Moreover, a theoretical model is derived to describe the A(lith)-t dependence accurately and to predict the tips' lifetime. Furthermore, an experiment involving DPN-based nanostructure fabrication demonstrates the importance of monitoring the tips' transport rate and lifetime. In addition to shedding light on the physical and chemical principles behind DPN, this study provides a comprehensive model for a quantitative analysis of the tips' behavior.

Ink‐on‐Probe Hydrodynamics in Atomic Force Microscope Deposition of Liquid Inks

“…The requirement for depositing “bleed spots” at the beginning of a liquid ink DPN experiment, before a “stable regime” of printing is reached, has been reported . Although there has been no dedicated studies of the decline in liquid ink deposition rate over a long term patterning procedure (as have been performed for molecular inks) the exponential nature of the decay has been noted . In our recent work, we suggested a decrease in the Laplace pressure gradient as the reason behind this decay in feature size …”

“…Beginning with our assumption that deposition rate is proportional to the volume of ink on the cantilever, a simple empirical model of exponential decay behaviour can be developed (detailed derivation included in the supplementary information). A similar line of argument has been followed to model the exponential decay in deposition rate for molecular ink DPN . The volume of dot “n” ( V dot(n) ) is related to the decay constant ( k ), the initial volume in the cantilever reservoir ( V res(0) ), and the deposited volume ( V dep ) by:…”

“…In particular, the stringent control of feature size is challenging when depositing minute liquid volumes. In contrast to molecular ink DPN, where ink depletion may constitute a minor adjustment to the prevailing model, the depletion of liquid inks causes a dramatic change in deposition rate. For example, it is accepted procedure to “bleed” a tip of excess liquid before “reproducible” dot sizes can be printed .…”

Development of Dip‐Pen Nanolithography (DPN) and Its Derivatives

“…Thorough understanding and prediction of material transfer in DPN would be highly beneficial in regard to the homogeneity of the lithography outcome . This would be crucial in the context of using DPN in industrial fabrication applications, but—as detailed above—is still not fully achieved (especially in regard to the liquid inks for their even more complicated transfer theory).…”

Direct‐Patterning SWCNTs Using Dip Pen Nanolithography for SWCNT/Silicon Solar Cells

“…The transport of materials of interest onto a substrate in DPN is dependent on many chemical and physical factors. Some of these factors include relative humidity, temperature, ink loading on the tip, and relative magnitude of the chemical interactions between the ink, tip, and substrate …”