In order to expand the processing utility of metallic aluminum as a material for nanometer-scale fabrication, we attempted to block oxidation of Al(111) surface in O-2 gas up to 1000 Torr, by predeposited organic monolayers A full monolayer of biphenyl-4 thiol (BPT), appropriately treated by electron-be am irradiation, exhibited a significantly enhanced robustness against oxidation, compared to clean Al(111)