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 language | English |
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Pages (from-to) | 62-68 |
Number of pages | 7 |
Journal | Surface Science |
Volume | 315 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 1994 Aug 10 |
Externally published | Yes |
Bibliographical note
Funding Information:We thank Professor 11C heol Jeon for taking AFM imageso f the MoS, sample and Dr. Ja-Yong Koo for constructiono f the STM unit. This work was supported in part by Korea Telecom and the Ministry of CommunicationsK, orea.
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
ASJC Scopus subject areas
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry