title: A bottom-up approach toward fabrication of ultrathin PbS sheets.
abstract: Two-dimensional (2D) sheets are currently in the spotlight of nanotechnology owing to high-performance device fabrication possibilities. Building a free-standing quantum sheet with controlled morphology is challenging when large planar geometry and ultranarrow thickness are simultaneously concerned. Coalescence of nanowires into large single-crystalline sheet is a promising approach leading to large, molecularly thick 2D sheets with controlled planar morphology. Here we report on a bottom-up approach to fabricate high-quality ultrathin 2D single crystalline sheets with well-defined rectangular morphology via collective coalescence of PbS nanowires. The ultrathin sheets are strictly rectangular with 1.8 nm thickness, 200-250 nm width, and 3-20 μm length. The sheets show high electrical conductivity at room and cryogenic temperatures upon device fabrication. Density functional theory (DFT) calculations reveal that a single row of delocalized orbitals of a nanowire is gradually converted into several parallel conduction channels upon sheet formation, which enable superior in-plane carrier conduction.
authors.affiliation: Centre for Advanced Materials, Indian Association for the Cultivation of Science, Kolkata 700032, India. camsa2@iacs.res.in
authors.forename: Somobrata
authors.initials: S
authors.lastname: Acharya
authors.forename: Bidisa
authors.initials: B
authors.lastname: Das
authors.forename: Umamahesh
authors.initials: U
authors.lastname: Thupakula
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Ariga
authors.forename: D D
authors.initials: DD
authors.lastname: Sarma
authors.forename: Jacob
authors.initials: J
authors.lastname: Israelachvili
authors.forename: Yuval
authors.initials: Y
authors.lastname: Golan
mesh_terms: D007854:Lead / Q000737:chemistry*; D036103:Nanotechnology; D053770:Nanowires / Q000737:chemistry*; D011789:Quantum Theory; D013440:Sulfides / Q000737:chemistry*
chemical_list: D013440:Sulfides; C018391:lead sulfide; D007854:Lead