Formation of stable Si–O–C submonolayers on hydrogen-terminated silicon(111) under low-temperature conditions

Abstract

SummaryIn this letter, we report results of a hydrosilylation carried out on bifunctional molecules by using two different approaches, namely through thermal treatment and photochemical treatment through UV irradiation. Previously, our group also demonstrated that in a mixed alkyne/alcohol solution, surface coupling is biased towards the formation of Si–O–C linkages instead of Si–C linkages, thus indirectly supporting the kinetic model of hydrogen abstraction from the Si–H surface (Khung, Y. L. et al. Chem. – Eur. J. 2014, 20, 15151–15158). To further examine the probability of this kinetic model we compare the results from reactions with bifunctional alkynes carried out under thermal treatment (<130 °C) and under UV irradiation, respectively. X-ray photoelectron spectroscopy and contact angle measurements showed that under thermal conditions, the Si–H surface predominately reacts to form Si–O–C bonds from ethynylbenzyl alcohol solution while the UV photochemical route ensures that the alcohol-based alkyne may also form Si–C bonds, thus producing a monolayer of mixed linkages. The results suggested the importance of surface radicals as well as the type of terminal group as being essential towards directing the nature of surface linkage.

Influences of Doping and Crystal Orientation on Surface Roughening upon Alcohol Grafting onto Silicon Hydride

“…Hence, we suspect that we could disregard all Hall effects at this temperature. Between both the n-and p-type substrate, the initial mechanism for the formation of Si-O-C bonds on the Si-H surface was relatively similar, occurring via the abstraction of hydrogen in the nucleophilic route [17,18] with the liberation of hydrogen during the process. However, from the start, the XPS Si2p spectrum on both the n-type silicon (111) and p-type silicon (111) showed the formation of Si-O-C bonding but their overall profiles were starkly different.…”

“…Previously, our group has also demonstrated the preference of hydrogenated silicon towards nucleophilic additions with alcohol ends of alkynes [6,17,18]. In fact, many reports have shown the susceptibility of alcohol grafting on silicon-hydride surfaces [4,7].…”

“…In a setup similar to our previous reports [6,17,18], all silicon wafers were cut into pieces (approximately 20 × 20 mm 2 ) and cleaned for 30 min in hot Piranha solution (95 • C, 1 vol 33% aqueous hydrogen peroxide to 3 vol 95-97% sulfuric acid). The surface was then transferred to an aqueous 2.5% hydrofluoric acid (HF) for a duration of 30 s to gently remove the native silicon oxide.…”

Preparation and characterization of photoactive antimicrobial graphitic carbon nitride (g-C3N4) films

“…The 532.6 eV peak likely corresponds to surface hydroxyl groups of the silicon sample holder, while the 533.9eV peak corresponds to chemisorbed water molecules on the surface of the ns- g -C 3 N 4 sample. 41 Importantly, the XPS spectrum of ns- g -C 3 N 4 contains no evidence for either C-O or C=O species that would indicate partial oxidation of the g -C 3 N 4 precursor.…”

Synthesis of phosphorus‐containing flame retardants and investigation of their flame retardant behavior in textile applications

“…The presence of the N1s peaks observed at 399 and 402 eV can be assigned to the carbon–nitrogen bonds. The peak observed for the char residue of the MKT‐2 coated sample observed at 102.4 eV was attributed to the SiOC bond …”