Investigation of the electrical properties of PLD-grown Bi2Te3 and Sb2Te2

Bismuth Telluride (Bi₂Te₃) and Antimony Telluride (Sb₂Te₃) were deposited using pulsed laser deposition (PLD) in the presence of Argon gas. The substrate temperature (T) was varied from 25°C to 450°C. Impedance spectroscopy and four point probe techniques were used to characterize the electrical properties of the films. Nyquist plots were obtained from these measurements for all the films, and an equivalent circuit model was developed to fit the experimental data. It was found that the values of series resistance obtained from the impedance spectroscopy are consistent with the values of the sheet resistance obtained from the four point probe instrument. The extracted values of the circuit elements explain the role of the grain boundary in determining the film impedance.