Suppression of current fluctuations in carbon nanotube field-effect transistors by applying alternating current

A method of suppressing current fluctuations in carbon nanotube field-effect transistors (CNTFETs) is proposed. We compared the time dependences of the drain current for direct current (DC) measurement and alternating current (AC) measurement with a lock-in amplifier. Drain-current fluctuations were highly suppressed by the AC with lock-in method in the small gate voltage regime. On the other hand, the current fluctuations for DC measurements were not so suppressed even if the integration time was increased from 80 mus to 10 ms. The frequency dependence of the current noise power spectra of the DC measurements was approximately 1/f while that of the AC measurement was approximately 1/f². These results indicate that the use of AC with a lock-in amplifier is very suitable for the suppression of current fluctuations.