Abstract
Consideration of the proximity effect, electron-phonon coupling, and size-quantization results in peculiar behavior of the critical temperature Tc of a contact containing superconducting and semimetal (or semiconductor) thin films. The method of thermodynamic Green's functions is applied. The dependence of Tc on the thickness of the barrier is discussed. Size quantization leads to additional oscillations of Tc and to the possibility of observing peculiar charge-density waves. The experimental data are discussed.