Porous SiC (PSC) freestanding layers were prepared via UV light-assisted electrochemical etching of an n-type 6H-SiC wafer. Fourier transform infrared (FTIR) spectroscopy and temperature-programmed desorption mass spectrometry (TPD-MS) were applied to characterize functional groups on the PSC surface and their chemical reactivity. It was shown that as-prepared PSC contains silanol groups, carboxylic acid groups, minor amounts of SiH and CH x groups, and also a carbon-rich surface phase. Annealing of PSC in air at 673 K resulted in the oxidation of the carbon-containing surface species and the formation of a hydrated silicon oxide surface layer. Using −Si(CH 3 ) 3 groups as a model, it was demonstrated that organic functional groups can easily be grafted on oxidized PSC via common silanization chemistry. Treatment of oxidized PSC with HF resulted in the formation of a surface terminated with methyl groups. It confirms that the walls of the PSC pores are constituted of the (0001) “silicon” crystal face of SiC and faces with similar atomic structure.
No takes yet. Share an insight, caveat, or question.
Алексеев et al. (2007) studied this question.