Single-walled carbon nanotube paper was surface oxidized with gaseous oxygen atoms produced by low-pressure: (1) vacuum UV (=104.8 and 106.7nm) photo-oxidation and (2) downstream microwave plasma discharge of an ArO2 mixture. X-ray photoelectron spectroscopy was used to detect the carbon- and oxygen-containing functional groups in the top 25nm of the sample's surface. Both methods produced a saturation level of ca. 12 at.% oxygen with the predominant formation of the epoxide/ether groups.