AlP/GaP quantum wells for implementing intersubband devices in the 30–60 μm wavelength region

A detailed study of inter-subband energy transitions in AlP quantum wells (QWs) based on valley-symmetry and effective-mass measurements using THz cyclotron resonance and quantum transport in AlP/GaP QWs is presented. We show that AlP/GaP QWs can serve as the basis for THz devices emitting in the 30-60 mum wavelength range that is inaccessible by other systems because of phonon band absorption.