Cu2WSe4 nanosheets were synthesized by hot-injection method and employed as interfacial layers between the p-Si and Au metal via spin coating technique. The capacitance–voltage (C–V) and conductance-voltage (G–V) measurements were performed on the Cu2WSe4/p-Si heterojunction device depending on wide range temperatures from 80 to 400 K by 40 K steps. The device exhibited decreasing capacitance behavior with increasing temperature at the inversion region because of the interface states and series resistance. The conductance values increased with increasing temperature owing to increasing free charge carriers. The series resistance (Rs) and interface states density (Nss) were extracted from C–V and G–V measurements and discussed in the details. The results highlighted that the electrical parameters are a strong function of the voltage and temperature. The Au/Cu2WSe4/p-Si device can be employed for controllable capacitor applications.