Stability of low-carrier-density topological-insulator Bi${}_2$Se${}_3$ thin films and effect of capping layers

Abstract

Although over the past number of years there have been many advances in the materials aspects of topological insulators (TI), one of the ongoing challenges with these materials is the protection of them against aging. In particular, the recent development of low-carrier-density bulk-insulating Bi${}_2$Se${}_3$ thin films and their sensitivity to air demands reliable capping layers to stabilize their electronic properties. Here, we study the stability of the low-carrier-density Bi${}_2$Se${}_3$ thin films in air with and without various capping layers using DC and THz probes. Without any capping layers, the carrier density increases by ~150% over a week and by ~280% over 9 months. In situ-deposited Se and ex situ-deposited Poly(methyl methacrylate) (PMMA) suppresses the aging effect to ~27% and ~88% respectively over 9 months. The combination of effective capping layers and low-carrier-density TI films will open up new opportunities in topological insulators.

14 pages, 3 figures

References in corpus (10)

• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Observation of Dirac plasmons in a topological insulator
• Rapid Surface Oxidation as a Source of Surface Degradation Factor for Bi2Se3
• Epitaxial growth of topological insulator Bi2Se3 film on Si(111) with atomically sharp interface
• Transport Properties of Topological Insulators: Band Bending, Bulk Metal-to-Insulator Transition, and Weak Anti-Localization
• Emergence of decoupled surface transport channels in bulk insulating Bi2Se3 thin films
• Surface versus bulk state in topological insulator Bi2Se3 under environmental disorder
• Terahertz Kerr and Reflectivity Measurements on the Topological Insulator Bi2Se3
• Restoring Pristine Bi2Se3 Surface with an Effective Se Decapping Process
• Robust topological surface states of Bi2Se3 thin films on amorphous SiO2/Si substrate and a large ambipolar gating effect

Cited by in corpus (13)

• Quantized Faraday and Kerr rotation and axion electrodynamics of a 3D topological insulator
• Solution to the hole-doping problem and tunable quantum Hall effect in Bi${}_2$Se${}_3$ thin films
• Finite-size and composition-driven topological phase transition in (Bi${}_{1-x}$In${}_x$)${}_2$Se${}_3$ thin films
• Optimization of the growth of the van der Waals materials Bi2Se3 and (Bi0.5In0.5)2Se3 by molecular beam epitaxy
• Progress in epitaxial thin-film Na3Bi as a topological electronic material
• Observation of terahertz second harmonic generation from Dirac surface states in the topological insulator Bi${}_2$Se${}_3$
• Tuning and Stabilizing Topological Insulator Bi2Se3 in the Intrinsic Regime by Charge Extraction with Organic Overlayers
• Spatially varying electronic dephasing in three dimensional topological insulators
• Suppressing carrier density in (BixSb1-x)2Te3 films using Cr2O3 interfacial layers
• Quantum Transport in Air-stable Na3Bi Thin Films
• Gate tunable quantum Hall effects in defect-suppressed Bi2Se3 films
• From classical to quantum regime of topological surface states via defect engineering
• Edge modes and Fabry-Perot Plasmonic Resonances in anomalous-Hall Thin Films