Attenuated total reflection Fourier transform infrared spectroscopy study of the adsorption of organic contaminants on a hydrogen-terminated Si(111) surface in air

The adsorption of organic contaminants on a hydrogen-terminated Si(111) surface was investigated using attenuated total reflection Fourier transform infrared spectroscopy. When the hydrogen-terminated Si(111) surface was exposed to dry air, the sharp Si–H monohydride peak became weaker and a broad component became visible in the lower wave-number region. Furthermore, a number of bands within the C–H stretching region were observed. The intensity of the sharp Si–H band was recovered to a certain extent and those of the broad component and the C–H bands decreased after the sample was rinsed in hexane. These results suggest that the contamination by organic adsorbates is not accompanied by a chemical bond formation.