Nanocoaxial Arrays

Michael J. Naughton

Department of Physics, Boston College

We discuss a novel nanoscale platform offering utility in nanophotonics, photovoltaics, neuroelectronics, and biochemical sensing. As subwavelength optical waveguides, arrays of coaxial electrodes can be used in a range of nanoscale manipulations of light, including optical nanoscopy, ultrathin film solar cells, high electrode-density retinal implants and discrete optical metamaterials. A modification of the basic structure enables the fabrication of highly sensitive biochemical sensors and a nanoscale neurointerface. We will report on aspects of these applications, with emphasis on radial junction solar cells. This structure allows for a unique decoupling of the optical and electronic length scales in photovoltaic devices, enabling highly efficient charge extraction in ultrathin films with highly efficient light collection. Devices exhibit strong optical absorption across the visible, and state-of-the-art power conversion efficiency using PV thinner than carrier (electron and hole) diffusion/drift lengths, suggesting a path to high efficiency solar power.