Electrical properties of crystalline PbxSn1−xTe0.5Se0.5 thin films

Electrical conductivity in the dark, σ, and thermoelectric power, S, of PbxSn1−xTe0.5Se0.5 films with x = 0.4, 0.6, 0.8, and 1 were studied for films annealed at 473 K in the temperature range 300–473 K, while the Hall voltage was investigated at room temperature. The temperature dependence of σ revealed an intrinsic conduction mechanism above 370 K, while for temperatures less than 370 K an extrinsic conduction is dominant. Both activation energy, ΔE1, and the energy gap, Eg, were found to decrease with increasing Sn content. This decrease of Eg with increasing Sn content revealed that band inversion exists. The variation of S with temperature revealed that the investigated samples are non-degenerate semiconductors with p-type conduction. Also, the Fermi energy, EF, was determined from the linear variation of S with 1/T in the intrinsic range. The compositional dependence of the room temperature Hall constant, RH (0.21–0.38 cm3/Coul.), hole carrier's concentration, p (2.9–1.6 × 1019 cm−3), Hall mobility, μH (0.88–0.03 cm2/V s), and effective mass, m∗/me (0.28–0.78) are given.