Parallel Patterning of Single Inorganic Nanowires with Arbitrary Composition Using Optoelectronic Tweezers

The synthesis of inorganic nanowires has advanced in the last decade to a point where a vast range of insulating, semiconducting, and metallic materials are available for use in heterogeneous, integrated optoelectronic devices at nanometer scales. However, a persistent challenge for the application of this family of materials has been the development of general strategies for the massively parallel manipulation of single nanowires with arbitrary composition. For instance, although laser tweezers are capable of addressing both insulating and semiconducting particles in three dimensions, extreme heating effects prevent the stable manipulation of metallic nanowires with highly focused lasers [1]. Optoelectronic tweezers (OET) have emerged in recent years as a powerful tool for the manipulation of micron scale particles, including living cells. When particles are much smaller than 1 micron the forces generated with OET typically are overcome by thermal (Brownian) fluctuations because DEP forces scale with material volume. In this presentation we demonstrate that individual semiconducting and metallic nanowires with diameters below 20 nm, are addressable with forces generated by optoelectronic tweezers (OET) [2]. Using 100,000x less optical power density than optical tweezers, OET is capable of transporting individual nanowires with speeds 4x larger than maximum speeds achieved by optical tweezers. A real-time array of silver nanowires is formed using photopatterned virtual-electrodes, demonstrating the potential for massively parallel assemblies. Digital video microscopy is used to quantify the dipole interaction between adjacent silver nanowires. The use of a photocurable polymer gel is presented as a means of fixing patterns of individual nanowires in place, opening up opportunities for novel device architectures.

References:

[1] Pauzauskie, P. J.; Radenovic, A.; Trepagnier, E.; Shroff, H.; Yang, P. D.; Liphardt, J. Nature Materials 2006, 5, 97-101.

[2] Jamshidi, A.; Pauzauskie, P. J.; Schuck, P. J.; Ohta, A. T.; Chiou, P. Y.; Chou, J.; Yang, P. D.; Wu, M. C. Nature Photonics 2008, 2, 85-89.