Coverage-dependent growth structures of sodium on the gaas(110) surface

Chunli Bai, Tomihiro Hashizume, Toshio Sakurai, Dong Ryul Jeon

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

The geometry and the coverage-dependent growth structures formed by Na deposition on the GaAs(llO) surface were studied by a field-ion scanning tunneling microscope (FI-STM) in an ultrahigh-vacuum. In the low-coverage regime at 300 K, Na adatoms reside on a bridge site encompassing one Ga and two As surface atoms to form linear chains along the substrate [110] direction. The Na-Na nearest-neighbor distance in this low-density chain structure is 0.8 nm. With slightly larger Na coverages, the chains became disordered. Some of them were packed closer to form domains showing a local 2x2 structure. None of high-density 2D ordered structures or low-density zigzag chains were observed, in contrast to the Cs/GaAs(llO) system. Additional Na adsorption resulted in the formation of three-dimensional disordered clusters. The saturation coverage of Na adsorption on the GaAs(llO) surface was determined to be about 0.1 ML (l ML =2 Na per substrate unit cell). The I-Vcurve recorded over the clean surface was consistent with published data for n-GaAs(llO), while no evidence of metallic characteristics was found in the I-V curves recorded over the various Na-covered surfaces.

Original languageEnglish
Pages (from-to)1401-1404
Number of pages4
JournalJapanese journal of applied physics
Volume32
Issue number3 S
DOIs
Publication statusPublished - 1993 Mar
Externally publishedYes

Keywords

  • Alkali metal
  • FI-STM
  • GaAs
  • Sodium
  • Thin film

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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