In this research, TGA technique was used for determining thermal and gravimetrical stability of Al/Sn/La2O3 nanostructures prepared by sol-gel and spin-coating methods. Structural properties and surface morphology of the films were investigated by different analysis methods. Energy dispersive X-ray spectroscopy and a map were used to make a quantitative chemical analysis of unknown materials. Electrical properties of the samples were measured by metal-dielectric-semiconductor through capacitance–voltage and current rate–voltage. The conduction mechanism in the electrical field below 0.12 MV/cm and in the temperature range of 335 K < T < 420 K was found to be ohmic emission. A model of thermal excitation is proposed to explain the mechanism of ohmic conduction current. The highest value of dielectric constant (k) was ~32 at T1 = 200°C with almost amorphous structure. The results showed that at T1 = 200°C the Al/Sn/La2O3 nanostructure has lower leakage current rate and higher capacitance than those for other samples because of almost amorphous structure.