Electrophysical Properties of Ge/Cr Thin Films

Electrophysical properties of the two-layer film systems based on Ge and Cr as two-layer film a-Ge/Cr/S or over Ge/Cr/S are studied. It is found that at a limited thickness of dGe ≈ 10-15 nm there is an inversion of sign value of ΔR/R = [R(Ge/Cr) – R(Cr)]/R(Cr) from ΔR/R < 0 (for dGe ≈ 10-15 nm) to ΔR/R > 0 (for dGe ≈ 10-15 nm). This result is explained by the formation of excitons of Wannier-Mott type that leads to a decrease in the concentration of free-carriers and, as a result of it, to the increase in the value of ΔR/R.