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Title: Stability of low-carrier-density topological-insulator Bi{sub 2}Se{sub 3} thin films and effect of capping layers

Although over the past number of years there have been many advances in the materials aspects of topological insulators (TIs), 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{sub 2}Se{sub 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{sub 2}Se{sub 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) suppress 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.
Authors:
 [1] ; ; ; ;  [2] ; ;  [3]
  1. Department of Materials Science and Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854 (United States)
  2. Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854 (United States)
  3. Department of Physics and Astronomy, The Institute for Quantum Matter, The Johns Hopkins University, Baltimore, Maryland 21218 (United States)
Publication Date:
OSTI Identifier:
22499238
Resource Type:
Journal Article
Resource Relation:
Journal Name: APL Materials; Journal Volume: 3; Journal Issue: 9; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AIR; BISMUTH SELENIDES; CARRIER DENSITY; DEPOSITS; ELECTRICAL INSULATORS; LAYERS; METHACRYLIC ACID ESTERS; SAFETY; SENSITIVITY; STABILITY; THIN FILMS