Article abstract


Nature Materials 6, 592 - 596 (2007)
Published online: 24 June 2007 | doi:10.1038/nmat1943

Subject Categories: Electronic materials | Nanoscale materials | Surface and thin films

Tunable electronic interfaces between bulk semiconductors and ligand-stabilized nanoparticle assemblies

Shannon W. Boettcher1, Nicholas C. Strandwitz2, Martin Schierhorn1, Nina Lock3, Mark C. Lonergan4 & Galen D. Stucky1,2


Interfaces between nanoscale and bulk electroactive materials are important for the design of electronic devices using solution-processed nanoparticles. We report that thin films of hexanethiolate-capped gold nanoparticles with a core diameter of 2.1plusminus0.4 nm deposited onto n-InP wafers form Schottky contacts whose barrier height can be actively tuned from 0.27plusminus0.03 to 1.11plusminus0.09 eV by electrochemically adjusting the nanoparticle Fermi level. This result is remarkable because interfacial barriers at conventional metal–semiconductor contacts are largely insensitive to the initial Fermi level of the metal. Furthermore, it highlights two general features of solution-processed nanoparticle assemblies in comparison with traditional bulk electronic materials: (1) the ability of ions to permeate the nanoparticle assembly enables the electrochemical injection of charges and hence active control of the Fermi level, and (2) ligand passivation of nanoparticle surfaces prevents interfacial reactions with the semiconductor that could otherwise lead to strong Fermi-level pinning.

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  1. Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA
  2. Materials Department, University of California, Santa Barbara, California 93106, USA
  3. Department of Chemistry, University of Aarhus, DK-8000 Aarhus C, Denmark
  4. Department of Chemistry, The Materials Science Institute, Oregon Nanoscience and Microtechnologies Institute, University of Oregon, Eugene, Oregon 97403, USA

Correspondence to: Galen D. Stucky1,2 e-mail: stucky@chem.ucsb.edu

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