Evolution of the Interface and Metal Film Morphology in the Vapor Deposition of Ti on Hexadecanethiolate Hydrocarbon Monolayers on Au

Abstract

The combination of in situ X-ray photoelectron spectroscopy, infrared reflection spectroscopy, atomic force microscopy, and time-of-flight secondary ion mass spectrometry are used to probe the nature of the evolving interface chemistry and metal morphology arising from Ti vapor deposition onto the surface of a CH(3)(CH(2))(15)S/Au{111} self-assembled monolayer (SAM) at ambient temperature. The results show that for a deposition rate of approximately 0.15 Ti atom.nm(-2).s(-1) a highly nonuniform Ti overlayer is produced via a process in which a large fraction of impinging Ti atoms do not stick to the bare SAM surface. The adsorbed atoms form isolated Ti clusters and react with CH(3) groups to form carbide products at the cluster-SAM interfaces. Further growth of Ti clusters appears to be concentrated at these scattered reaction centers. The SAM molecules in the local vicinity are subsequently degraded to inorganic products, progressing deeper into the monolayer as the deposition proceeds to give an inorganic/organic nanocomposite. A continuous overlayer does not form until metal coverage approaches approximately 50 Ti atoms per SAM molecule. These data indicate that for applications such as molecular device contacts the use of Ti may be highly problematic, suffering from both a highly nonuniform contact area and the presence of extensive inorganic products such as nonstoichiometric carbides and hydrides.

An atomic layer deposition reactor with dose quantification for precursor adsorption and reactivity studies

“…37,38 In these systems, however, film growth results from metal atom adsorption and condensation onto cool (25 • C) substrates. Hence, absolute sticking probabilities onto SAMs may be calculated by assuming the sticking of evaporants is unity onto the bare metal.…”

Interaction of D2 with Ti-Adsorbed Polyaniline and Implication for Hydrogen Storage

“…Ti Clustering on PANI and TiO 2 Substrates. Recent investigations on the initial stage of interface formation in vapor deposition of Ti on various self-assembled monolayers [19][20][21][22] and on nitrogen and halogen containing polymer surfaces 23 have shown that a large fraction of incident Ti atoms do not stick to these organic substrates at room temperature but form isolated clusters, indiscriminatingly reacting with the substrates. Isolated Ti clusters may also form on PANI, which may be the reason for the small number of D 2 molecules adsorbed per Ti.…”

Effect of nitrogen on mechanical, oxidation and structural behaviour of Ti–Si–B–C–N nanocomposite hard coatings deposited by DC sputtering

“…The Ti2p presents three peaks at 458.4, 456.4 and 454.3 eV, and another are at 464.4, 462.4 and 460.2 eV correspondingly to the Ti2p 3/2 and Ti2p 1/2 . The peaks at 458.4 and 464.4 eV correspond to Ti 4+ in TiO 2 , at 456.4 and 462.4 eV correspond to TiC, but the peaks may be also identified at 462.4 eV because of Ti 4+ 2p 3/2 from TiO 2 , again another remaining one peak at 454.3 and 460.2 eV correspond to TiB 2 (Fig. a) .…”

“…The XPS of Ti2p, Si2p, B1s and C1s core-level spectra for the same samples is shown in Fig. 8 [45,46] at 456.4 and 462.4 eV correspond to TiC, [47,48] but the peaks may be also identified at 462.4 eV because of Ti 4+ 2p 3/2 from TiO 2 , [49] again another remaining one peak at 454.3 and 460.2 eV correspond to TiB 2 (Fig. 8a).…”