Electrical responses of a carbon nanotube thin-film transistor to MeV proton irradiation in air.

We used protons with incident energy of 3.30 MeV to irradiate a carbon nanotube thin-film transistor (CNTTFT) to study its electrical response in air environment. The drain current (ID) was monitored by applying a constant gate voltage (VGS) to the CNTTFT; proton irradiation was turned on and off at a beam intensity of 50,000 cps. ID increased at a negative VGS of −20 V and decreased at a positive VGS of +10 V during proton irradiation. For both VGS values, ID began to recover after proton irradiation. According to the calculations for the energy loss of protons, the incident protons deposited their energy on the CNTTFT. Micro-Raman analysis revealed that no structural change in the CNT was caused by the incident protons. The reversible electrical responses of the CNTTFT to proton irradiation should be applicable to the detection and dosimetry of MeV incident protons in air