Oxidation effect on the ultrafast carrier dynamics of GaTe studied by terahertz spectroscopy

Abstract

Effect of oxygen on the physical properties of GaTe is investigated by optical pump–terahertz probe spectroscopy. Oxygen erosion in GaTe leads to significant reductions in lifetime and transient conductivity. Terahertz emission is also evaluated. Terahertz radiation intensity gradually dies away with increasing air exposing time. Such phenomena are attributed to the trapping of photogenerated carriers by oxygen–introduced defects, which can result in the reduction of the carrier density, acceleration of the photocarrier relaxation, and impediment of the terahertz emission.