Fabrication and Characterization of an Enhancement-Mode Planar Resonant Tunneling Transistor

We report the fabrication and characterization of a planar resonant tunneling transistor (PRTT) using a GaAs/AlGaAs heterostructure wafer. Our PRTT operates as an enhancement-mode device, and shows the negative differential resistance (NDR) modulated with the gate bias in an extremely wide range (from the fully depleted dot to the dot in a single-electron transistor regime). This NDR spectrum represents a full, gate-bias-modulated evolution of the 0-D states in a quantum dot. Our data are also consistent with the ground ( $E_{1}$) and the first excited state ($E_{2}$) of the Fock–Darwin states.