Temperature-dependent spectral linewidths of terahertz Bloch oscillations in biased semiconductor superlattices

We investigate temperature-dependent spectral linewidths of Bloch oscillations in biased semiconductor superlattices experimentally and theoretically. The spectral linewidth in a GaAs-based super-lattice determined by terahertz emission spectroscopy becomes larger gradually as temperature increases from 80 to 320 K. This behavior can be quantitatively reproduced by a microscopic theory of the spectral linewidth that has been extended to treat the phonon scattering and interface roughness scattering of electrons on a Wannier-Stark ladder. A detailed comparison between the terahertz measurements and theoretical simulations reveals that the LO phonon absorption process governs the increase in the spectral linewidth with increasing temperature. Published by AIP Publishing.