High-performance carbon nanotube field-effect transistors with electron mobility of 39.4 cm2V-1s-1 using anion-pi interaction doping

Abstract

Single-walled carbon nanotube (SWNT) is desirable next generation semiconductor for flexible, transparent and even stretchable with exceptional electrical characteristics. Here, high-performance n-type semiconducting SWNT field-effect transistors (s-SWNT-FETs) are achieved by chemical doping using anion-pi interaction between SWNT and anion of tetrabutylammonium fluoride (TBAF) salt. The Fermi level (EF) of SWNT shifts to the con-duction band edge with increasing dopant concentration. The doped s-SWNT-FETs exhibit significant improve-ment in electron mobility (39.4 cm2V- 1s- 1) with high current on/off ratio (>104) compared to those of un-doped device. The doping using anion-pi interaction leads to populate electron density of channel and reduces both channel and contact resistance by 99.0% and 99.6%. Excess carriers introduced by the doping compensate traps by shifting the EF toward conduction band edge. The doped device showed improved current stability after 10 h of bias stress test, while the current of undoped FET decreased by 40.4%. Finally, flexible FETs with TBAF doped s-SWNT network are demonstrated on polyethylene naphthalate substrate and show stable operation after 2000 times bending test.