Temperature degradation of the gain transition in terahertz quantum cascade lasers - the role of acoustic phonon scattering

The temperature degradation in terahertz quantum cascade lasers is investigated with the focus on the role acoustic phonon scattering. A self-energy describing the electron-acoustic phonon interaction is derived and used to study the importance in transport and optical properties. We observe a strong degradation of the gain peak with temperature. Despite the very small coupling to electrons, the exclusion of acoustic phonon scattering alters the current and peak gain in the order of 5%. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei