A Bottom-Up Approach toward Fabrication of Ultrathin PbS Sheets

作者：Acharya Somobrata^*; Das Bidisa; Thupakula Umamahesh; Ariga Katsuhiko; Sarma D D; Israelachvili Jacob; Golan Yuval

来源：Nano Letters, 2013, 13(2): 409-415.

DOI：10.1021/nl303568d

• Nanowires
• ultrathin sheet
• coalescence
• activation energy
• DFT calculations
• transport

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 mu m 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.

• 出版日期2013-2