Massively parallel low-cost pick-and-place of optoelectronic devices by electrochemical fluidic processing

We describe a novel electrochemical technique for the nonlithographic, fluidic pick-and-place assembly of optoelectronic devices by electrical and optical addressing. An electrochemical cell was developed that consists of indium tin oxide (ITO) and n -type silicon substrates as the two electrode materials and deionized water (R = 18 MOmega) as the electrolytic medium between the two electrodes. 0.8-20-microm-diameter negatively charged polystyrene beads, 50-100-microm-diameter SiO(2) pucks, and 50-microm LED's were successfully integrated upon a patterned silicon substrate by electrical addressing. In addition, 0.8-microm-diameter beads were integrated upon a homogeneous silicon substrate by optical addressing. This method can be applied to massively parallel assembly (>1000 x 1000 arrays) of multiple types of devices (of a wide size range) with very fast (a few seconds) and accurate positioning.