Unveiling the ultrafast optoelectronic properties of 3D Dirac semi-metal Cd 3 As 2

We employ ultrafast optical-pump terahertz-probe spectroscopy and ultrafast THz emission spectroscopy to investigate the ultrafast charge carrier dynamics in the 3D Dirac semi-metal Cd 3 As 2 . We extract the temperature-dependent electron mobility (16,000cm2V−1s−1 at 5K) for Cd 3 As 2 nanowire ensemble. We also demonstrate strong THz emission from both Cd 3 As 2 single crystal and nanowires, whose polarity depends strongly on incident angle and pump polarisation.