Semiconducting single-walled carbon nanotube (s-SWNT) arrays are produced via a procedure analogous to a surfactant-assisted decontamination process. Aligned individual SWNT arrays grow on a quartz surface as a mixture of metallic SWNTs (m-SWNTs) and s-SWNTs. They are immersed in a sodium dodecyl sulfate (SDS) solution, and the SDS molecules selectively adsorb onto m-SWNTs. This SDS coating minimizes the interaction between m-SWNTs and the substrate, thus the m-SWNTs are easily washed off during ultrasonication while the s-SWNT arrays remain on the substrate. The percentage of s-SWNTs in the arrays can be higher than 90%.