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A Bottom-Up Approach toward Fabrication of Ultrathin PbS Sheets

2013; American Chemical Society; Volume: 13; Issue: 2 Linguagem: Inglês

10.1021/nl303568d

1530-6992

Somobrata Acharya, Bidisa Das, Umamahesh Thupakula, Katsuhiko Ariga, D. D. Sarma, Jacob N. Israelachvili, Yuval Golan,

Copper-based nanomaterials and applications

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.