In this paper an electro-absorption modulator (EAM) based on plasmonic material along with different dielectric materials were investigated. The study focuses on the performance matrices of the device based on four different dielectric materials such as hafnium dioxide (HfO2), silicon nitride (Si3N4), boron nitride (hBN), and silicon dioxide (SiO2). A finite element method (FEM) is used to carry out the investigated results like insertion loss (IL), extinction ratio (ER), and figure of merit (FOM). The device yielded a very high ER of 35.42 dB/µm and an IL of 0.02 dB/µm at 1.55 µm wavelength. A modulation frequency (f3dB) of 0.46 THz, 1.50 THz, 2.39 THz, and 4.24 THz was achieved for the EAMs with HfO2, Si3N4, hBN, and SiO2as the dielectric material, respectively. Also, the investigated EAM with different dielectric materials has the potential to be integrated in Photonic Integrated Circuits (PICs).