Fabrication and characterization of GaAs/AlGaAs planar resonant tunneling transistor

We have demonstrated electron transport in enhancement mode in-plane-gate (IPG) quantum dot (QD) transistors. A deep etched trench allows a large positive bias on the IPG, with negligible leakage current. Such enhancement mode operation has made it possible to populate ultra-small QDs with electrons. Strong NDR peaks and SET are observed in a wide gate bias window. The position of the NDR peaks systematically moves with the change of gate bias until, and also after the SET regime is reached. The size of the QD is estimated from the SET data, giving quantum energy level spacing consistent with the evolved NDR positions.