Passivation of GaAs nanocrystals by chemical functionalization

Matthew C. Traub, Julie S. Biteen, Bruce S. Brunschwig, Nathan S Lewis

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

The effective use of nanocrystalline semiconductors requires control of the chemical and electrical properties of their surfaces. We describe herein a chemical functionalization procedure to passivate surface states on GaAs nanocrystals. Cl-terminated GaAs nanocrystals have been produced by anisotropic etching of oxide-covered GaAs nanocrystals with 6 M HCl(aq). The Cl-terminated GaAs nanocrystals were then functionalized by reaction with hydrazine or sodium hydrosulfide. X-ray photoelectron spectroscopic measurements revealed that the surfaces of the Cl-, hydrazine-, and sulfide-treated nanocrystals were As-rich, due to significant amounts of As0. However, no As0 was observed in the photoelectron spectra after the hydrazine-terminated nanocrystals were annealed at 350° C under vacuum. After the anneal, the N 1s peak of hydrazine-exposed GaAs nanocrystals shifted to 3.2 eV lower binding energy. This shift was accompanied by the appearance of a Ga 3d peak shifted 1.4 eV from the bulk value, consistent with the hypothesis that a gallium oxynitride capping layer had been formed on the nanocrystals during the annealing process. The band gap photoluminescence (PL) was weak from the Cl- and hydrazine- or sulfide-terminated nanocrystals, but the annealed nanocrystals displayed strongly enhanced band-edge PL, indicating that the surface states of GaAs nanocrystals were effectively passivated by this two-step, wet chemical treatment.

Original languageEnglish
Pages (from-to)955-964
Number of pages10
JournalJournal of the American Chemical Society
Volume130
Issue number3
DOIs
Publication statusPublished - Jan 23 2008

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hydrazine
Passivation
Nanoparticles
Nanocrystals
Hydrazine
Surface states
Sulfides
Photoelectrons
Photoluminescence
gallium arsenide
Anisotropic etching
Semiconductors
Gallium
Surface Properties
Vacuum
Binding energy
Oxides
Chemical properties
Electric properties
Energy gap

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Passivation of GaAs nanocrystals by chemical functionalization. / Traub, Matthew C.; Biteen, Julie S.; Brunschwig, Bruce S.; Lewis, Nathan S.

In: Journal of the American Chemical Society, Vol. 130, No. 3, 23.01.2008, p. 955-964.

Research output: Contribution to journalArticle

Traub, Matthew C. ; Biteen, Julie S. ; Brunschwig, Bruce S. ; Lewis, Nathan S. / Passivation of GaAs nanocrystals by chemical functionalization. In: Journal of the American Chemical Society. 2008 ; Vol. 130, No. 3. pp. 955-964.
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