For an s-wave superconductor/semiconductor/ferromagnetic-insulator structure, the proximity effect can induce the energy gap in the semiconductor rather than the superconducting pair potential of its microscope Hamiltonian. As a result, it is questionable to realize topological superconducting states in that structure.
@article{arxiv.1010.4390,
title = {Proximity effect can induce the energy gap rather than superconducting pair potential},
author = {Zhongwen Xing and Mei Liu},
journal= {arXiv preprint arXiv:1010.4390},
year = {2010}
}