Magnetic‐TEGFET: Transistor Without a Gate

Abstract

Low‐temperature current–voltage characteristics of n‐type GaAs/GaAlAs quantum wells delta‐doped in GaAs channel with Be acceptors are studied in the presence of a magnetic field. Negatively charged acceptor ions localize 2D conduction electrons by a combined effect of a quantum well and magnetic field parallel to the growth direction. In acceptor‐doped samples, the Hall electric field plays the role of the gate voltage. It is shown that at magnetic fields as weak as 1.5 T (or higher), the drain current reaches a constant value independent of the drain voltage. This phenomenon is due to the electron localization resulting in the decrease of conducting electron density in the crossed‐field configuration. The above special behavior of acceptor‐doped GaAs/GaAlAs heterostructures is exploited to realize a device called Magnetic‐TEGFET (Magnetic Two‐dimensional Electron Gas Field Effect Transistor) operating at low temperatures. The elimination of the gate in the studied transistor suppresses the gate‐to‐drain leakage current, which, in the standard TEGFETs, results in the electronic shot noise.