Achievement

The direct electrical excitation of surface plasmons is extremely attractive for chip-based plasmonic circuits and would enable numerous device applications, such as new, high-efficiency solid state lighting sources. Currently, electrical excitation of surface plasmons requires high energy electron beams. Alternatively, direct electron injection from tunneling junctions into plasmonic waveguides would be a highly practical method for the electrical excitation of plasmons, however this approach requires reliable fabrication of metallic gaps in the < 10 nm size range, which is below the limit of even the highest resolution e-beam fabrication methods. We have developed a hybrid nanofabrication procedure that reliably produces sub-10 nm tunneling junctions in planar geometries with a working device efficiency of greater than 80%. These structures are currently being integrated into surface plasmon waveguides to characterize the properties of surface plasmon generation.