Electrically Driven Optical Antennas Based on Template Dielectrophoretic Trapping.

An electrically driven optical antenna (EDOA) provides a nanoscale light-emitting scheme that is appealing for biosensors, plasmonic displays, and on-chip optoelectronic circuits. The EDOA (consisting of metal nanoparticles (NPs)) excited by inelastic tunneling electrons has attracted broad interest due to its terahertz modulation bandwidth and microelectronics-compatible dimensions. Currently, the efficient fabrication of EDOA is hampered by the ultrasmall size of NPs and the requirement of controllable preparation. Here, we overcome this limitation by accurately positioning thiol-covered gold NPs onto predesigned electrodes using dielectrophoresis trapping. The combination of a high-quality molecule tunnel barrier and the template trapping ensures that the EDOA can operate stably in ambient conditions. More importantly, the template trapping allows fabrication of EDOA with different numbers and arrangements of NPs by controlling the size and orientation of the template. This technology provides a way to fabricate controllable optoelectronic devices based on NPs and is promising for compact and smart photonic devices.