Temperature-dependent terahertz spectra and terahertz emission of GaTe

Abstract The terahertz spectra and terahertz emission characteristics of Gallium telluride (GaTe) as a function of temperature were studied by terahertz spectroscopy system, including terahertz time-domain spectroscopy, optical pump-terahertz probe spectroscopy and terahertz emission spectroscopy. The temperature range is 20 K–300 K. The temperature-dependence terahertz transmittance and dielectric properties, photocarrier recombination dynamics and terahertz radiation properties of GaTe are analyzed. As the temperature increases, thermal expansion and lattice vibration intensify, resulting in accelerated phonon scattering and reduced relaxation time. Meanwhile, due to the acceleration of the relaxation process, the carriers are rapidly recombined, which improves the terahertz transmittance of GaTe. Further, enhanced terahertz emission of GaTe was observed at low temperatures. This is because the excitation energy at low temperatures is more easily converted into transient photocurrents than energy dissipation. This work provides technical support for the fabrication of GaTe-based optoelectronic devices.