Scanning tunneling microscopy investigation of the surface structures of natural MoS2

Jeong Sook Ha, Hee Sook Roh, Seong Ju Park, Jae Yel Yi, El Hang Lee

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Scanning tunneling microscope (STM) images of natural MoS2 revealed protrusions with a diameter of 30-40 Å and ring-type structures with two different diameters of 40 and 80 Å on the surface. The STM images were taken varying the tip bias voltage from -0.04 to -1.1 eV. Ring-type structures existed in the whole range of tip bias voltages used, but the ring intensity which was subtracted by the background drastically decreased at tip bias voltages beyond -0.9 eV. Atomic force microscope (AFM) images of the same MoS2 sample did not show such structures. In order to understand the origin of the ring-type structures observed on the natural MoS2 surface, the impurities in the sample were analyzed by using glow discharge mass spectrometry (GDMS). The concentrations of the major impurities such as V and Ti were comparable to the average number density of ring structures on the sample. STM and AFM images suggest that the ring-type structures appear as an electronic effect due to the sinuous band structure caused by two kinds of band bending near the impurities included in the MoS2 sample.

Original languageEnglish
Pages (from-to)62-68
Number of pages7
JournalSurface Science
Volume315
Issue number1-2
DOIs
Publication statusPublished - 1994 Aug 10
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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