Pulsed THz emission from wurtzite phase catalyst-free InAs nanowires

The wurtzite phase catalyst-free InAs nanowires were investigated under femtosecond optical pulse photoexcitations. It was found that the THz radiation emission mechanisms depend on an exciting laser beam polarization, namely, the plasma oscillations for perpendicular to nanowire optical electric fields, and the ballistically moving carrier separation for the parallel polarization fields. The energetic distance between Γ7c and Γ8c conduction bands was experimentally determined to be 0.5 eV.