To study the characteristics of transition metal dichalcogenides (TMDCs) in the THz regime, several kinds of terahertz modulators based on TMDCs were fabricated. The properties of these terahertz modulators were measured on a terahertz time-domain spectroscopy system. An 808-nm laser was used as the controller of the THz modulator. Briefly, as the power of the pumping laser increased, the amplitude of the transmission THz wave decreased. To explain these results, an analysis based on photoconductivity was presented. Additionally, the influence of the boundary defects was pointed out to give further explanation about the working mechanism of the TMDC-based THz modulator. Based on this analysis, most of the behavior of TMDCs in THz modulators could be understood.
