Thermal chemistry of biacetyl on Si(100)

Abstract

Articles you may be interested inThermal chemistry of copper(I)-N,N′-di-sec-butylacetamidinate on Cu(110) single-crystal surfaces J. Vac. Sci. Technol. A 30, 01A114 (2012); 10.1116/1.3658381Adsorption and electron-induced polymerization of methyl methacrylate on Ru ( 10 1 ¯ 0 ) Thermal and electron-driven chemistry of CCl 4 on clean and hydrogen precovered Si(100) X-ray photoelectron spectroscopy ͑XPS͒, temperature programmed desorption ͑TPD͒, and high-resolution electron energy loss spectroscopy ͑HREELS͒ were used to study the adsorption and decomposition ͑for temperatures between 160 and 1100 K͒ of biacetyl (CH 3 COCOCH 3 ) on Si͑100͒. We conclude from peak positions in the C(1s) and O(1s) XPS spectra that biacetyl initially adsorbs by binding through the carbonyl -bonds either forming a di-bonded form of biacetyl or completely cleaving the carbonyl double bond. In TPD, biacetyl molecularly desorbs at 185 K for the multilayer and between 263 and 285 K for the monolayer indicated in TPD. TPD also indicates ketene, methane, and hydrogen desorption at 330, 823, and 870 K, respectively. On the surface, there is evidence in XPS that all CvO containing fragments completely dissociate or desorb by 700 K. Above 700 K, hydrogen begins transferring to the surface as shown by the appearance of a peak in HREELS at 2103 cm Ϫ1 ( Si-H ). Surface hydrogen recombines with methyl groups and other surface hydrogen producing methane ͑823 K͒ and molecular hydrogen ͑870 K͒. SiO desorbs at 1010 K and is reflected in XPS by total loss of the O(1s) signal. Finally, heating to 1100 K results in SiC formation.

Chemical manipulation of multifunctional hydrocarbons on silicon surfaces

“…Despite the fact that no reaction barrier was predicted for the [4 + 2] addition, the desorption of 2,3-butanedione at 263 K suggested that chemisorption competed with a simple desorption even from a very reactive Si(100)-2×1 substrate. The 263 K desorption peak shifted to 285 K for higher doses but was clearly distinguishable from the multilayer desorption reported at 185 K for 12.5 L dose [119]. This behavior is very similar to that reported by Teplyakov group for vinyltrimethylsilane [224], nitroalkanes [227] and nitrobenzene [224].…”

“…Further theoretical work ascribed this absorption band to the alkene stretch and confirmed the ease of the heteroDiels-Alder reaction [169]. The thermal chemistry of 2,3-butanedione on Si(100)-2×1 has been studied starting with a temperature as low as 160 K by Armstrong et al [119] and this chemistry seems to be rather similar to other reactive compounds. Despite the fact that no reaction barrier was predicted for the [4 + 2] addition, the desorption of 2,3-butanedione at 263 K suggested that chemisorption competed with a simple desorption even from a very reactive Si(100)-2×1 substrate.…”

“…As described above in Section 3.2, the Diels-Alder analogue has been well-established on a Si(100)-2×1 for butadienes and 1,3-cyclohexadiene and later confirmed for other structurally similar compounds. Interestingly, the [4 + 2] adduct was ruled out for 2,3-butanedione based mainly on the observation of a vibrational band at 1670 cm −1 , initially assigned to a ν C=O mode [119]. Further theoretical work ascribed this absorption band to the alkene stretch and confirmed the ease of the heteroDiels-Alder reaction [169].…”

The structures of physisorbed and chemisorbed formic acid on Si(111)-7×7

“…Thus the existence of bridging formate containing two equivalent O-atoms may be excluded. The peak at 532.1 eV is assigned to the oxygen attached to the silicon, in excellent agreement with the binding energy of CH 3 O-Si formed through the dissociative reaction of methanol on Si(1 1 1)-7 · 7 [29]. Compared to the physisorption O 1s spectrum, a large binding energy shift of the hydroxyl oxygen atom suggests the breakage of the O-H bond.…”

Adsorption of Phenyl Isothiocyanate on Si(001): A 1,2-Dipolar Surface Addition Reaction

“…Finally, recent investigations have shown that these cycloaddition reactions on the Si(001) surface are not limited solely to alkenes. We have demonstrated the possibility of a cycloaddition reaction involving a NN bond, while White et al have shown that a CO bond may also undergo a [2 + 2] addition on Si(001) …”