title: Wafer-scale patterning of lead telluride nanowires: structure, characterization, and electrical properties.
abstract: Nanowires of lead telluride (PbTe) were patterned on glass surfaces using lithographically patterned nanowire electrodeposition (LPNE). LPNE involved the fabrication by photolithography of a contoured nickel nanoband that is recessed by approximately 300 nm into a horizontal photoresist trench. Cubic PbTe was then electrodeposited from a basic aqueous solution containing Pb(2+) and TeO(3)(2-) at the nickel nanoband using a cyclic deposition/stripping potential program in which lead-rich PbTe was first deposited in a negative-going potential scan and excess lead was then anodically stripped from the nascent nanowire by scanning in the positive direction to produce near stoichiometric PbTe. Repeating this scanning procedure permitted PbTe nanowires 60-400 nm in width to be obtained. The wire height was controlled over the range of 20-100 nm based upon the nickel film thickness. Nanowires with lengths exceeding 1 cm were prepared in this study. We report the characterization of these nanowires using X-ray diffraction, transmission electron microscopy and electron diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy (XPS). The surface chemical composition of PbTe nanowires was monitored by XPS as a function of time during the exposure of these nanowires to laboratory air. One to two monolayers of a mixed Pb and Te oxide are formed during a 24 h exposure. The electrical conductivity of PbTe nanowires was strongly affected by air oxidation, declining from an initial value of 2.0(+/-1.5) x 10 (4) S/m by 61% (for nanowires with a 20 nm thickness), 55% (for 40 nm), and 12% (for 60 nm).
authors: Department of Chemistry, University of California, Irvine, CA 92697-2025, USA.
authors: Yongan
authors: Y
authors: Yang
authors: David K
authors: DK
authors: Taggart
authors: Matthew A
authors: MA
authors: Brown
authors: Chengxiang
authors: C
authors: Xiang
authors: Sheng-Chin
authors: SC
authors: Kung
authors: Fan
authors: F
authors: Yang
authors: John C
authors: JC
authors: Hemminger
authors: Reginald M
authors: RM
authors: Penner
mesh_terms: D003460:Crystallization / Q000379:methods*; D004553:Electric Conductivity; D007854:Lead / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties; D013691:Tellurium / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: D046911:Macromolecular Substances; C009495:titanium dioxide; D007854:Lead; D014025:Titanium; C026660:tellurous acid; D013691:Tellurium