REAL-SPACE TRANSFER IN HETEROJUNCTION STRUCTURES

An n-type GaAs buried region and an undoped GaAs layer separated by the potential barrier caused by the presence of GaAlAs material show the formation of a channel for electrons. When a voltage relative to the source is applied to the buried region, the upper interface moves below the Fermi level and a channel is induced. The conduction mechanisms in the device are detailed and the electrical characteristics give a set of output I-d(V-d) curves. Negative differential resistances are observed and the electrical mechanism corresponds to the real-space transfer of carriers from the channel to the N-GaAs collector layer. A channel for electrons is formed at the interface of a wide band gap material (GaAlAs) and an undoped GaAs compound. The experiments results show that carriers heated by the electric field parallel to the GaAlAs barrier are injected into the adjacent collector electrode.