Terahertz quantum cascade emitters based on AlAs/GaAs

Quantum cascade structures designed for terahertz emission with barriers made of AlAs show a higher efficiency in electroluminescence measurements than those with Al0.15Ga0.85As barriers. Magnetotransport data allows us to explain this observation. We attribute the higher efficiency to an increased fraction of current undergoing the luminescent transition. There is less intersubband scattering in the binary alloy barriers than in the ternary alloy.