Work function tuning at Au-HfO{sub 2} interfaces using organophosphonate monolayers

Journal Article · Mon May 09 00:00:00 EDT 2016 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4949019· OSTI ID:22591704

Kwan, Matthew; Cardinal, Thomas; Ramanath, Ganpati ^[1]; Mutin, P. Hubert ^[2]

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1. Materials Science and Engineering Department, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)
2. Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-IM2-ENSCM-UM1, Université Montpellier 2, CC 1701, Place Eugène Bataillon, 34095 Montpellier Cedex 5 (France)

We show that introducing organophosphonate nanomolecular monolayers (NMLs) at Au-HfO{sub 2} interfaces shift the effective work function by 0.2 eV ≥ ΔΦ{sub eff} ≥ −0.6 eV, due to NML body and bonding dipoles. Electron spectroscopy of NML-Au, NML-HfO{sub 2,} and Au-NML-HfO{sub 2} structures indicate that the Au-NML bond strength is the major factor. Au-NML covalent bonding yields ΔΦ{sub eff} ∼ − 0.2 eV, while weak bonding yields ΔΦ{sub eff} ∼ 0.6 eV. In contrast, NMLs on HfO{sub 2} decrease Φ{sub eff} by ∼0.4 eV due to competing contributions from NML-HfO{sub 2} bonding strength and NML orientation. These findings are relevant for nanomolecularly tailoring the electronic properties of metal–ceramic interfaces for applications.

• OSTI ID: 22591704
• Journal Information: Applied Physics Letters, Vol. 108, Issue 19; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CERAMICS
COVALENCE
DIPOLES
ELECTRON SPECTROSCOPY
HAFNIUM OXIDES
INTERFACES
METALS
ORIENTATION
TUNING
WORK FUNCTIONS
YIELDS