A novel mechanism of negative differential conductance (NDC) in HEMT-like structures with tunneling between the gate and the channel has been predicted theoretically by us (Ref. 17). The mechanism is an inherent property of tunnel Schottky structures with 2D channels. Our experimental results (Ref. 18) indicate that the mechanism does indeed lead to decrease in the tunnel conductance in such structures and that, with certain modifications of the structures, it should lead to NDC. The developed theory is in very good quantitative agreement with a wide range of various experimental tunnel-spectroscopy data on the tunnel Schottky contacts with 2D channels (see, e.g., Ref. 19). Such structures can become a basis for novel active devices for THz frequencies.

Band diagram of a tunnel Schottky barrier with a narrow 2D channel, formed at the heterointerface between the GaAs and AlGaAs layers.

© Michael Feiginov

Tunnel Schottky contact with 2D channel