Matrix-assisted dip-pen nanolithography and polymer pen lithography

Abstract

The controlled patterning of nanomaterials presents a major challenge to the field of nanolithography because of differences in size, shape and solubility of these materials. Matrix-assisted dip-pen nanolithography and polymer pen lithography provide a solution to this problem by utilizing a polymeric matrix that encapsulates the nanomaterials and delivers them to surfaces with precise control of feature size.

Figure 1

Illustration of matrix-assisted dip-pen nanolithography (MA-DPN) and arrays generated by MA-DPN. a, Scheme illustrating the process involved in patterning surfaces by MA-DPN. b, AFM topographical image of a pattern of three dots of PEG-AuNPs of different sizes on an Au surface created by intentionally varying the dwell time (1, 3 and 10 s) of the tip on the surface. c, AFM topographical image of a pattern of dot arrays of PEG-Fe₃O₄ MNP dots of different sizes on a Si/SiO_x surface created by intentionally varying the dwell time (1, 3 and 10 s) of the tip on the surface. d, AFM topographical image of a pattern of dot arrays of PEG-C₆₀ of different sizes on a Si/SiO_x surface created by intentionally varying the dwell time (1, 3 and 10 s) of the tip on the surface.

Figure 2

Arrays of dots created by matrix-assisted polymer pen nanolithography (MA-PPL). a, AFM topographical image of a 6×6 dot array of PEG-Fe₃O₄ MNP ink on a HMDS-coated Si/SiO_x surface created by intentionally varying the dwell times of the polymer tips on the surface (1, 3 and 10 s). b, Height profile of one line of PEG-Fe₃O₄ MNPdots demonstrating control of feature size with varying dwell times. c, An optical microscopy image of a large- scale pattern of PEG-Fe₃O₄ MNP dots (~1 μm width, 1 s dwell time) created on a HMDS-coated Si/SiO_x surface by a 62,500 pen array. The inset is an AFM topographical image of the 12×12 dot pattern of PEG-Fe₃O₄ ink written by a single polymer pen.

Figure 3

MA-PPL printed dot arrays on metallic, insulating, and semiconducting surfaces. a, A 3×3 dot array of PEG-Fe₃O₄ MNP ink patterned by MA-PPL on an Au substrate by intentionally varying the dwell time (1, 3 and 10s). b, A 3×3 dot array of PEG-Fe₃O₄ MNP ink patterned by MA-PPL on a Si/SiO_x substrate by varying the dwell time (1, 3 and 10s). c, A 3a3 dot array of PEG-Fe₃O₄ MNP ink patterned by MA-PPL on a GaAs substrate by intentionally varying the dwell time (1, 3 and 10s).

Figure 4

A photoresponsive transistor by MA-DPN. a, Illustration of the deposition of the C₆₀-PEG ink between electrodes by MA-DPN. b, AFM topographical image of the photoresponsive transistor. The four electrodes are connected by two perpendicular lines of the C₆₀-PEG ink. c, The I–V curve of the transistor in the dark (black trace) and under white light from a 50 W tungsten-halogen lamp (red trace).