Photoresist Removal\nby an Aluminum Protective Layer\nto Improve the Performance of Carbon Nanotube Thin-Film Transistors

Photolithography is a key process in the fabrication\nof carbon\nnanotube devices. However, the strong interactions between organic\nphotoresists and single-wall carbon nanotube (SWCNT) films result\nin residual photoresists on their surfaces after lithography, which\nincreases the interfacial resistance between the SWCNTs and between\nthe SWCNTs and the metallic electrodes. To reduce the contamination\nof the photoresist in the photolithography process, we introduce an\nultrathin aluminum metal protective layer to isolate the photoresist\nand the SWCNT film in the photolithography process, which is prepared\nvia simple thermal evaporation. The protective layer can be removed\nby etching with the developer and subsequent acid solution without\naffecting the patterns, while the SWCNT film maintains a clean surface.\nThe resulting SWCNT thin-film transistors exhibit an order of magnitude\ngreater on-state current and carrier mobility than those without the\nprotective layer because a substantial decrease in the resistance\nbetween the SWCNTs and between the SWCNT film and the metallic electrodes.\nThis work provides an important scheme for the fabrication of high-performance\ncarbon-based devices.