Quantum response of carbon nanotube quantum dots to terahertz wave irradiation

Abstract

Single-electron transport measurements have been carried out at 1.5 K on single-wall carbonnanotube (SWCNT) quantum dots (QDs) under terahertz (THz) irradiation with afrequency of 2.5 THz. The most important finding in this study was new side-peaks thatappeared only under the THz irradiation. From the detailed analysis with energy scalesassociated with the QDs, we conclude that the side-peaks originate from thephoton-assisted tunnelling (PAT) of an electron in the QD to the drain electrode. Thepresent THz-PAT is the first observation in QDs because of the larger energyscales in a SWCNT QD, compared with those of standard semiconductor QDs.