Effects of gallium arsenide passivation on scanning tunneling microscope excited luminescence

E. E. Reuter, S. Q. Gu, P. W. Bohn, J. F. Dorsten, G. C. Abeln, J. W. Lyding, S. G. Bishop

Research output: Contribution to journalConference article

Abstract

An ambient scanning tunneling microscope (STM) was used to excite luminescence in p-type epitaxial GaAs with four separate surface preparations: bare GaAs, Au layer, sulfur-monochloride layer, and one monolayer of octa-decyl-thiol. The STM with tungsten tip was operated at a constant tunnel current of 5 nA during a +1 V bias applied to the sample and the resulting tip to sample distance was fixed during a higher voltage bias pulse which excited luminescence. The luminescence intensity increased rapidly with increasing bias voltage for all passivation types with the octa-decyl-thiol passivation achieving the highest STM excited luminescence (STMEL) of 3500 photons/sec at 4 V bias. Above about 4 V the luminescence from the octa-decyl-thiol and sulfur-monochloride passivated samples fell off irreversibly, indicating that the sample surface had been modified. The Au passivated and unpassivated samples showed no such luminescence drop up to 4.8 V, the highest bias employed. Photoluminescence (PL) studies of the samples showed that PL intensities exhibited a weaker dependence upon passivation type than did STMEL intensities, a result consistent with the assertion that STMEL is more sensitive to the surface properties of the sample than is PL.

Original languageEnglish (US)
Pages (from-to)119-124
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume380
DOIs
StatePublished - Jan 1 1995
EventProceedings of the 1995 MRS Spring Meeting - San Francisco, CA, USA
Duration: Apr 17 1995Apr 20 1995

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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