High yield production of semiconducting p-type single-walled carbon nanotube thin-film transistors on a flexible polyimide substrate by tuning the density of ferritin catalysts

We report on a simple method for fabricating pure p-type single-walled carbon nanotube (SWCNT) thin-film transistors (TFTs) on flexible polyimide substrates without selective removal of metallic SWCNTs from the as-grown CNT films. The density of the SWCNTs was controlled by tuning the concentration of ferritin catalyst, resulting in the control of the metallic percolation pathways in the SWCNT TFTs. For a ferritin solution diluted by 1/2000, approximately 60% of the pristine SWCNT TFTs showed p-type behavior with larger on/off current ratios, (Ion/Ioff > 104) and a high photosensitivity to the exposure of UV/visible light.