Electrical properties of hot wall deposited PbTe–SnTe thin films

Polycrystalline Pb$_{1-x}$Sn$_{x}$Te ($0.0\le x\le 1.0$) telluride alloys were synthesized by the direct fusion technique. Thin films of these materials were prepared by a hot wall deposition method on glass substrates at T$_{sub}$ =230–330$^\circ$ C and in a vacuum of about 10$^{-5}$ Torr. The microstructure of the films was characterized by XRD, SEM, EDX and AES. The films showed a natural cubic structure. The thin films' microstructure consisted of densely packed grains with dimensions of 50–300 nm and crystallite growth direction is perpendicular to substrate plane. The asgrown Pb$_{1-x}$Sn$_{x}$Te films showed p-type conductivity. Thermoelectric measurements of the films showed high values for the room-temperature Seebeck coefficient ranging, from 20 to 400 $\mu$V $\cdot$ K$^{-1}$, for SnTe to PbTe thin films, respectively. The conductivity of the films was in the range of 3 $\cdot$ 10$^{1}$–1 $\cdot$ 10$^{4}$ $\Omega^{-1}\cdot$ cm$^{-1}$.