Few-layer Nanoplates of Bi2Se3 and Bi2Te3 with Highly Tunable Chemical Potential

Abstract

Topological insulator (TI) represents an unconventional quantum phase of matter with insulating bulk bandgap and metallic surface states. Recent theoretical calculations and photoemission spectroscopy measurements show that Group V-VI materials Bi2Se3, Bi2Te3 and Sb2Te3 are TI with a single Dirac cone on the surface. These materials have anisotropic, layered structures, in which five atomic layers are covalently bonded to form a quintuple layer, and quintuple layers interact weakly through van der Waals interaction to form the crystal. A few quintuple layers of these materials are predicted to exhibit interesting surface properties. Different from our previous nanoribbon study, here we report the synthesis and characterizations of ultrathin Bi2Te3 and Bi2Se3 nanoplates with thickness down to 3 nm (3 quintuple layers), via catalyst-free vapor-solid (VS) growth mechanism. Optical images reveal thickness-dependant color and contrast for nanoplates grown on oxidized silicon (300nm SiO2/Si). As a new member of TI nanomaterials, ultrathin TI nanoplates have an extremely large surface-to-volume ratio and can be electrically gated more effectively than the bulk form, potentially enhancing surface states effects in transport measurements. Low temperature transport measurements of a single nanoplate device, with a high-k dielectric top gate, show decrease in carrier concentration by several times and large tuning of chemical potential.

6 figures

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Cited by in corpus (14)

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• Vapor-Solid Growth of High Optical Quality MoS2 Monolayers With Near-Unity Valley Polarization
• Rapid Surface Oxidation as a Source of Surface Degradation Factor for Bi2Se3
• Growth of High-Mobility Bi2Te2Se Nanoplatelets on hBN Sheets by van der Waals Epitaxy
• Synthesis of SnTe Nanoplates with {100} and {111} Surfaces
• Thermal Stability and Anisotropic Sublimation of Two-Dimensional Colloidal Bi2Te3 and Bi2Se3 Nanocrystals
• NMR Probe of Metallic States in Nanoscale Topological Insulators
• Synthesis and characterisation of nanomaterials of the topological crystalline insulator SnTe
• Two-dimensional magnetotransport in Bi2Te2Se nanoplatelets
• Van der Waals epitaxial growth of topological insulator Bi${}_{2-x}$Sb${}_x$Te${}_{3-y}$Se${}_y$ ultrathin nanoplate on electrically insulating fluorophlogopite mica
• Indications of the topological transport by the universal conductance fluctuations in the Bi2Te2Se microflakes
• An ab initio investigation of Bi${}_2$Se${}_3$ topological insulator deposited on amorphous SiO${}_2$