Superconducting $T_c$ enhancement in weakly disordered Ge-covered tin films

We report on the variation of the superconducting transition temperature with the electrical resistance ratio in weakly disordered Ge-covered tin films deposited at room temperature. The normal-state sheet resistance $R_N^{\square }$ varied between 0.2<$R_N^{\square }$<4.2 Ω/□. The transition temperature shows a maximum when the resistance ratio ∼7.5. Results are discussed in the light of the Anderson localization.