Suppressed absolute negative conductance and generation of high-frequency radiation in semiconductor superlattices

TL;DR

This paper demonstrates how to suppress destructive space-charge instabilities in semiconductor superlattices to enable room-temperature generation of high-frequency radiation at microwave and THz frequencies using harmonic gain.

Contribution

It introduces an effective method to suppress electric field domains in superlattices, facilitating high-frequency radiation generation at room temperature.

Findings

Suppressed space-charge instabilities enable high-frequency gain.

Unbiased superlattices with microwave pumping produce harmonic gain.

The method allows room-temperature operation of THz devices.

Abstract

We show that space-charge instabilities (electric field domains) in semiconductor superlattices are the attribute of absolute negative conductance induced by small constant and large alternating electric fields. We propose the efficient method for suppression of this destructive phenomenon in order to obtain a generation at microwave and THz frequencies in devices operating at room temperature. We theoretically proved that an unbiased superlattice with a moderate doping subjected to a microwave pump field provides a strong gain at third, fifth, seventh, etc. harmonics of the pump frequency in the conditions of suppressed domains.