Adsorption of H2S and H2O on a cylindrical Ge sample

Adsorption of partially and fully dissociatedH2Smolecules on the Si(001) and Ge(001) surfaces

“…Similarly, the Ge͑001͒ surface is fastly covered with the H 2 S gas saturating at half a monolayer coverage at 300 K, and is characterized by three intense and sharp peaks. 4 For both surfaces, the three peaks are attributed to the formation of SH species, advocating partial dissociation of H 2 S into SH and H. The adsorption of H 2 S at an elevated temperature of 550 K on both Si͑001͒ and Ge͑001͒ results in peaks which are attributed to atomically adsorbed sulfur or a surface sulfide. Ranke and co-workers 3,4 suggest that the adsorbate is most likely fully dissociated into S and 2H.…”

“…4 For both surfaces, the three peaks are attributed to the formation of SH species, advocating partial dissociation of H 2 S into SH and H. The adsorption of H 2 S at an elevated temperature of 550 K on both Si͑001͒ and Ge͑001͒ results in peaks which are attributed to atomically adsorbed sulfur or a surface sulfide. Ranke and co-workers 3,4 suggest that the adsorbate is most likely fully dissociated into S and 2H. A similar behavior has also been recently found for H 2 O on Si͑001͒ by Weldon et al 5 At 625 K, an oxygen insertion into the Si-Si dimer bond is found more favorable than OH dissociation on thermodynamical grounds using both the density functional cluster calculations and surface infrared absorption spectroscopy.…”

The Adsorption and Decomposition of H2S on Ge(001): An STM Study

“…This adsorption is a useful analogue of the technologically important water-silicon(001) system; it is also considered to be a route to ordered sulphur deposition. Kuhr and Ranke [1] estimated a saturation coverage of 0.5 ML following 100 L exposure at room temperature (1 ML corresponds to 6×10 14 cm −2 ). Their UPS data for this adsorbate is indicative of dissociative adsorption of HS; exposure at the higher temperature of 277 • C leads to a very different spectrum which is attributed to adsorbed sulphur.…”

A first principles study of H2S adsorption and decomposition on a Ge(100) surface

“…[16][17][18] Previously, the S-passivation on Ge(100) surface has been investigated using low-energy electron diffraction (LEED), 8,19 high-resolution electron-energy loss spectroscopy (EELS), 20 ultraviolet photoelectron spectra (UPS), 21 X-ray photoelectron spectra (XPS), 22 temperature programmed desorption (TPD), 23 Near edge X-ray absorption ne structure (NEXAFS) 24 and multiple internal reection-Fourier transform infrared spectrometer (MIR-IR). 25 Kuhr and Ranke 21 showed in their UPS study that, H 2 S adsorbs dissociatively at 300 K on a Ge surface; then decomposes completely to form sulfur at 550 K. To understand the suldation of the Ge(100) surfaces and its possible passivating reactions, we choose H 2 S as a passivant to be adsorbed on the Ge(100) surface. In this study, we report ab initio theoretical investigations to provide a complete description of the adsorption effects and thermal decompositions of H 2 S on Ge(100) surface.…”