Quantum dots for terahertz generation

Abstract

Nanostructures made of semiconductors, such as quantum wells and quantum dots (QD),are well known, and some have been incorporated in practical devices. Here we focus onnovel structures made of QDs and related devices for terahertz (THz) generation. Theirpotential advantages, such as low threshold current density, high characteristictemperature, increased differential gain, etc, make QDs promising candidates for lightemitting applications in the THz region. Our idea of using resonant tunneling through QDsis presented, and initial results on devices consisting of self-assembled InAs QDs in anundoped GaAs matrix, with a design incorporating a GaInNAs/GaAs short periodsuperlattice, are discussed. Moreover, shallow impurities are also being explored forpossible THz emission: the idea is based on the tunneling through bound states ofindividual donor or acceptor impurities in the quantum well. Initial results on deviceshaving an AlGaAs/GaAs double-barrier resonant tunneling structure are discussed.