Ru and RuO2 Thin Films by XPS

Abstract

Ru and RuO2 thin films are considered to be new electrode materials for dynamic random access memories (DRAMs) and ferroelectric nonvolatile memories because of their low resistivity and good thermal and chemical stabilities. In this study these thin films were pepared by reactively sputtering a Ru metal target (99.9% purity) in an argon and oxygen atmosphere. XPS spectra were collected with a PHI 1600 spectrometer equipped with a monochromatic Al Kα x-ray source and a multichannel detector. This report includes XPS spectra of Ru 3d and O 1s core regions for these samples. The binding energy of Ru 3d5/2 is determined as 280.0 and 280.8 eV for Ru and RuO2 films, respectively. The presence of a small amount of Ru with higher oxidation states, such as Ru6+ and Ru8+, is shown at the surface of the RuO2 thin film.

Characterization of a Spent Ru/C Catalyst after Gasification of Biomass in Supercritical Water

“…From our own measurements and in agreementwithliterature(seeTable3, [28][29][30][31][32][33][34] ) the 280.2 eV signal can be related to metallic ruthenium. This is in agreement with the detection of metallic ruthenium by in situ XAS measurements.…”

“…[e.g. 31,32] and our own measurements on a reference material [39] find binding energies of about 280.8 eV, however some [28][29][30] report higher binding energies (281.4-282.0 eV). The latter values are similar to the one recorded on our fresh catalyst (~281.5 eV).…”

“…by Bagus et al [43] Pedersen and Lunsford [44] Ta ble 3. Comparison of Ru3d 5 / 2 and Ru3p 3 / 2 peak positions of ruthenium metal and oxides determined by XPS; literature data [28][29][30][31][32][33][34] and own measurements.…”

The Active State of Supported Ruthenium Oxide Nanoparticles during Carbon Dioxide Methanation

“…XPS at Ru 3d level allows resolving the oxidation states of Ru. 46 As expected, 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Ru was found to be oxidized on the calcined sample (Figure 1a, Figure 5B-a) but easily reduced under H 2 at 250 °C to a fully metallic state (Figure 1b, Figure 5B-b). Contrary to other preparation routes, 47 RuO 2 preformed nanoparticles on TiO 2 were fully reduced under H 2 and no oxidized ruthenium sites were observed at the interface with the oxide, as shown by the fully reduced state observed on Figure 1d.…”

Hydrogen mediated transport of Sn to Ru film surface

“…4͒, where appropriate fitting requires inclusion of two spin-splitted pairs: metallic pair with Ru 3d 5/2 peak located at 280.0 eV and oxidic one shifted by 0.7 eV toward higher binding energies ͑Ru 3d 5/2 at 280.7 eV͒. 43 Ru 3d 3/2 photoemission overlaps with C 1s lines from adventitious carbon and CO, which are present on the surface of as installed sample. However, C 1s contribution ͑not shown in Fig.…”