Electrical properties of crystalline Pb xSn 1− xTe 0.5Se 0.5 thin films

Abstract

Electrical conductivity in the dark, σ, and thermoelectric power, S, of Pb x Sn 1− x Te 0.5Se 0.5 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, Δ E 1, and the energy gap, E g, were found to decrease with increasing Sn content. This decrease of E g 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, E F, was determined from the linear variation of S with 1/ T in the intrinsic range. The compositional dependence of the room temperature Hall constant, R H (0.21–0.38 cm 3/Coul.), hole carrier's concentration, p (2.9–1.6 × 10 19 cm −3), Hall mobility, μ H (0.88–0.03 cm 2/V s), and effective mass, m ∗/ m e (0.28–0.78) are given.