The Effects of Temperature and Scan Velocity on Direct-write Dip-pen Nanolithography Using Molecular Dynamics Simulation

The two important controllable parameters in the dip-pen nanolithography (DPN) process, such as writing temperature and velocity, are used to investigate the related effects on mechanisms of transference of alkanethiol self-assembled monolayer (SAM), transfer number, gasification number, and nanowire formation using molecular dynamics simulations. The simulated results show that the molecular transport ability during the direct-write process from the tip to the substrate is dependent on writing temperature and velocity, because the molecules have high kinetic energy and undergo fast diffusion when the temperature is increased; high transfer ability occurs at a slow writing velocity. The nanowire thickness and length increase significantly with increasing writing temperature, and its length increases much faster than its thickness (height). When the writing temperature is increased, transfer number and gasification number of the molecules become dramatically larger. The transfer number of ink molecules increases with decreasing writing velocity.