The current work presents the possibility of tuning the dielectric parameters by changing the temperature, voltage, and frequency. The unusual behavior of some parameters was attributed to the lattice mismatch constant between gallium arsenide (GaAs) and silicon (Si) and the crystal defects between them. In this article, a thin GaAs film has been grown on Si substrates by liquid phase epitaxial (LPE) as n-GaAs/p-Si heterostructure. Despite the lattice mismatch between GaAs and Si, our interest in this article was focused on investigating the electrical and dielectric properties by I-V and C-V measurements. This was distinguished in the behavior of the dielectric properties such as the imaginary part of modules M″, the real and imaginary part of electrical conductivity σ^′ac and σ^″ac, respectively, which has not been seen before at high frequencies.