The unique electronic properties of single-walled carbon nanotubes (SWNTs) can be used to generate a current response from visible light. Vertically aligned single-walled carbon nanotube arrays were created on an optically transparent electrode (fluorine-doped tin oxide coated glass, FTO) by a self-assembly process using the hydrophobicity of the nanotube side walls and chemical treatment of both the nanotubes and the FTO substrate. This leads to arrays of SWNTs chemically attached to the substrate that, when exposed to visible light, exhibited a prompt current response (4.7 μA/cm2, ≤200 ms) and a voltage of ∼40 mV. This photoresponse behavior was investigated by modifying the attachment conditions and also the SWNT treatment procedures. The nanotube arrays were found to have a tunable current and voltage response and serve as a possible scaffold for further functionalization.