Charge carrier dynamics of ZnSe by optical-pump terahertz-probe spectroscopy

The optical properties and transient dynamics of ZnSe were studied by terahertz time-domain spectroscopy (THz-TDS) and optical-pump terahertz probe (OPTP) spectroscopy, respectively. From the THz time-domain signal, the frequency-dependent absorption coefficient and index of refraction of ZnSe were calculated. It follows that the values appear to be similar with those in literatures. The complex permittivity and conductivity of ZnSe were then derived. It was found out that ZnSe exhibit a more dominant dielectric response by the Jonscher´s model. It was also noted that the Drude model did not fit the conductivity data. A UV-pump pulse was introduced to observe the transient dynamics. ZnSe has a faster charge carrier relaxation compared with Si and Ge.