Sub-picosecond far-infrared transient-grating measurements of electron cooling in InAs and GaSb

Abstract

Compared to GaAs, little is known about hot-electron dynamics in narrow-gap semiconductors such as InAs and GaSb. These materials have a smaller bandgap, a smaller effective electron mass and a smaller electron-phonon coupling constant in comparison with GaAs. To investigate the dynamics of hot electrons in these materials, it is necessary to use mid- to far-infrared optical pulses with a photon energy low enough to avoid the generation of holes by (multi-photon) interband electron-hole pair generation. [1,2] Here, we show results of transient-grating experiments in n-type InAs and GaSb in which we time-resolve the ultrafast electron cooling of an electron distribution after optical excitation with intense sub-picosecond far-infrared pulses.