Direct patterning of CdSe quantum dots into sub-100 nm structures.

Ordered, two-dimensional cadmium selenide (CdSe) arrays have been fabricated on indium-doped tin oxide (ITO) electrodes using the pattern replication in nonwetting templates (PRINT) process. CdSe quantum dots (QDs) with an average diameter of 2.7 nm and a pyridine surface ligand were used for patterning. The PRINT technique utilizes a perfluoropolyether (PFPE) elastomeric mold that is tolerant of most organic solvents, thus allowing solutions of CdSe QDs in 4-picoline to be used for patterning without significant deformation of the mold. Nanometer-scale diffraction gratings have been successfully replicated with CdSe QDs.

Simple demonstration of visible evanescent-wave enhancement with far-field detection.

We demonstrate the fabrication of a simple metamaterial-diffraction grating device that both amplifies and converts evanescent waves into propagating ones. This is the most accessible example of such phenomena reported until now (to our knowledge), as it requires few thin film layers, operates in the visible, and can be probed with traditional optics. The metamaterial exhibits amplification of evanescent waves generated from total internal reflection. The device was fabricated over 1 cm2 using pulsed-laser deposition and a pattern-replication technique.

The Patterning of Sub-500 nm Inorganic Oxide Structures.

Elastomeric perfluoropolyether molds are applied to pattern arrays of sub-500 nm inorganic oxide features. This versatile soft-lithography technique can be used to pattern a wide range of materials; in this work inorganic oxides including TiO2 , SnO2 , ZnO, ITO, and BaTiO3 are patterned on a variety of substrates with different aspect ratios. An example of TiO2 posts is shown in the figure.