Coulomb peak shifts under terahertz-wave irradiation in carbon nanotube single-electron transistors

The authors have studied the effect of terahertz irradiation on single-electron transistors (SETs) based on single-wall carbon nanotubes, and have observed that the radiation generates Coulomb peak shifts. Time-resolved measurements of the terahertz response have revealed that the peak-shift signal has very long time constants, measured in seconds, and that the time trace of the signal after the terahertz irradiation is turned off deviates from a single-exponential curve. These experimental results suggest that the terahertz irradiation causes a charging process in trap states in the close vicinity of the SET, leading to a change in its effective gate voltage.