Cheon Lab

Main Links

Logo and Main Menu

Full Menu

Research

Search

Total: 142 data, Page 15 of 15

2. [Evolutionary Nanomaterials & Nanodevices] Jinwoo Cheon, John E Gozum, Gregory S Girolami
Chemical Vapor Deposition of MoS2 and TiS2 Films From the Metal−Organic Precursors Mo(S-t-Bu)4 and Ti(S-t-Bu)4
Chemistry of materials, 9 (8), 1847-1853
 (Aug 14, 1997)

The deposition of MoS2 and TiS2 thin films from the metal-organic precursors Mo(S-t-Bu)4 and Ti(S-t-Bu)4 has been investigated. Stoichiometric films with low levels of oxygen and carbon contaminants can be grown at temperatures between 110 and 350 °C and low pressure. The films are amorphous when grown at these low temperatures and have granular morphologies in which the grains are 30−90 nm in diameter, the larger grain sizes being observed at higher deposition temperatures. For the MoS2 deposits, the electrical conductivity was ∼1 Ω-1cm-1. For both precursors, the organic byproducts generated during deposition consist principally of isobutylene and tert-butylthiol; smaller amounts of hydrogen sulfide, isobutane, di-tert-butyl sulfide, and di-tert-butyl disulfide are also generated. A β-hydrogen abstraction/proton-transfer mechanism accounts for the distributions of the organic byproducts seen during the deposition of MoS2 and TiS2 films. Our results differ in some respects from those

1. [Evolutionary Nanomaterials & Nanodevices] Jinwoo Cheon, Lawrence H Dubois, Gregory S Girolami
Mechanistic studies of the thermolysis of tetraneopentyltitanium (IV). 2. Solid state and ultra-high-vacuum studies of the chemical vapor deposition of TiC films
Journal of the American Chemical Society, 119 (29), 6814-6820
 (Jul 23, 1997)

The chemical pathway responsible for the conversion of the organotitanium compound tetraneopentyltitanium to titanium carbide has been studied under chemical vapor conditions and on single crystals in ultra-high vacuum. For every equivalent of TiNp4 consumed in the deposition process, 3.28 equiv of neopentane and 0.16 equiv of isobutane are produced; other organic species are also formed but in relatively small amounts. About 93% of the carbon and hydrogen originally present in the precursor can be accounted for in these products. Thermolysis of the specifically deuterated analogue Ti(CD2CMe3)4 yields a 2.25:1 ratio of neopentane-d3 and neopentane-d2; this result combined with a kinetic isotope effect of 4.9 at 385 K shows unequivocally that the first step in the deposition pathway under CVD conditions is α-hydrogen abstraction. The α-hydrogen abstraction step produces 1 equiv of neopentane and a titanium alkylidene, which undergoes further α- (and eventually γ-) hydrogen activation pr

List

Copyright and Address

  • ADDRESS Department of Chemistry. 50 Yonsei-ro, Seodaemun-gu, Seoul 03722
  • TEL +82-2-2123-4748
  • FAX +82-2-2123-4640
  • EMAIL lee7626@yonsei.ac.kr
  • © Cheon Group | Yonsei University. All Right Reserved

Display Page Loading Image

Top