Chemical Effects of Ne+ Bombardment on the MoS2(0001) Surface Studied by High-Resolution Photoelectron Spectroscopy
Abstract
The effect of 1-keV Neon cation bombardment on the clean Molybdenum disulfide (0001) - 1 x1 surface with fluences between 4 x 10 to the 14th power Ne(+)/sq. cm was studied using high-resolution photoelectron spectroscopy excited with synchrotron radiation. Spectra of the Mo-3d and S-2p core levels were measured with photon energies that ensured that the kinetic energy of their photoelectrons was the same, resulting in the same depth being probed for both core levels. For lower fluences, S vacancy defect formation occurs in the MoS2 lattice, with the concurrent formation of a small amount (<10%) of dispersed elemental molybdenum Mo(0). For fluences greater than approx. 1 x 10 to the 16th power Ne(+)/sq. cm, the Mo(0) is the predominant species in the surface region, while the remaining species consists of amorphous MoS(2-x)and polysulfide species. Valence band spectra taken with photon energies of 152 eV and 225 eV were consistent with the core level results. The movement of the valence band maximum toward the Fermi level indicated the formation of a metallic surface region. A qualitative depth distribution of the chemical species present after Ne(+) bombardment was determined. The result indicate that the preferential sputtering of sulfur over molybdenum occurs predominantly through a mechanism involving chemical bonding effects, specifically, through the preferential emission of polysulfide ions over other species in the bombarded region.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 28, 1989
- Accession Number
- ADA207734
Entities
People
- Jeffrey R. Lince
- Jory A . Yarmoff
- Malina M. Hills
- Paul D. Fleischauer
- Thomas B. Stewart
Organizations
- The Aerospace Corporation