Role
of surfaces in nanowire electronics, photonics, and sensors: challenges A. A. Talin, F. Leonard, E. Lai, L. Hunter, B. Rokad, G. Wang Nanowires based on virtually every class of materials have been synthesized and demonstrated to have new, interesting and potentially very useful properties that stem from such features as carrier confinement and morphology/crystal structure unique to the nanoscale dimension. Inherent to the nanowire geometry is the prominent role of the surface in determining the physical and chemical properties. Indeed, numerous studies have touted the high surface-to-volume ratio of nanowires, and demonstrated their potential application to chemical and biological sensing. Yet, the high surface to volume ratio inherent to nanowires can also present a formidable challenge to realizing many nano-electronic and nano-optics applications. Specifically, surfaces of III-V compounds such as GaAs and GaN, which are particularly desirable for photonic applications due to their direct bandgap, are notorious for have high densities of surface states. These surface states usually result in pinned Fermi level and depletion regions that can extend hundreds of nanometer into the bulk (thus consuming the entire nanowire!). In my talk I will describe our on-going work in fabricating, characterizing, and modeling of semiconducting nanowires, with particular emphasis on the role of the surface, and the challenges (or ‘opportunities’) that it presents. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000 |