Terahertz sensing with a carbon nanotube/two-dimensional electron gas hybrid transistor

We report on a highly sensitive terahertz (THz) detector based on a carbon nanotube (CNT) transistor, which is integrated with a two-dimensional electron gas (2DEG) in a GaAs/AlGaAs heterostructure. The operation principle of this device is that the CNT transistor senses electrical polarization induced by terahertz-excited electron-hole pairs in the 2DEG. The magnetic field dependence of the terahertz response signal (CNT current) is shown to follow features of cyclotron resonance of the 2DEG, indicating the validity of the above mechanism. The utilization of the present device structure and mechanism has enabled the detection of a small number of terahertz photons.