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Title: Protective capping and surface passivation of III-V nanowires by atomic layer deposition

Low temperature (∼200 °C) grown atomic layer deposition (ALD) films of AlN, TiN, Al{sub 2}O{sub 3}, GaN, and TiO{sub 2} were tested for protective capping and surface passivation of bottom-up grown III-V (GaAs and InP) nanowires (NWs), and top-down fabricated InP nanopillars. For as-grown GaAs NWs, only the AlN material passivated the GaAs surface as measured by photoluminescence (PL) at low temperatures (15K), and the best passivation was achieved with a few monolayer thick (2Å) film. For InP NWs, the best passivation (∼2x enhancement in room-temperature PL) was achieved with a capping of 2nm thick Al{sub 2}O{sub 3}. All other ALD capping layers resulted in a de-passivation effect and possible damage to the InP surface. Top-down fabricated InP nanopillars show similar passivation effects as InP NWs. In particular, capping with a 2 nm thick Al{sub 2}O{sub 3} layer increased the carrier decay time from 251 ps (as-etched nanopillars) to about 525 ps. Tests after six months ageing reveal that the capped nanostructures retain their optical properties. Overall, capping of GaAs and InP NWs with high-k dielectrics AlN and Al{sub 2}O{sub 3} provides moderate surface passivation as well as long term protection from oxidation and environmental attack.
Authors:
; ; ; ;  [1] ; ;  [2] ; ;  [3] ;  [4]
  1. Department of Micro- and Nanosciences, Micronova, Aalto University, P.O. Box 13500, FI-00076 (Finland)
  2. Research School of Physics & Engineering, Department of Electronic Materials Engineering, Australian National University, Canberra ACT 2601 (Australia)
  3. Department of Applied Physics and Nanomicroscopy Center, Aalto University, P.O. Box 15100, FI-00076 (Finland)
  4. School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, S-164 40 Kista (Sweden)
Publication Date:
OSTI Identifier:
22492392
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 6; Journal Issue: 1; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; AGING; ALUMINIUM NITRIDES; ALUMINIUM OXIDES; DIELECTRIC MATERIALS; FILMS; GALLIUM ARSENIDES; GALLIUM NITRIDES; INDIUM PHOSPHIDES; LAYERS; NANOWIRES; OPTICAL PROPERTIES; OXIDATION; PASSIVATION; PHOTOLUMINESCENCE; SURFACES; TEMPERATURE DEPENDENCE; TITANIUM NITRIDES; TITANIUM OXIDES