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Surface structures and properties of Sn islands grown on superconducting substrate 2H-NbSe2 (0001) are studied using low temperature scanning tunneling microscopy or spectroscopy.The pure face-centered cubic (fcc) structure of Sn surface is obtained.Superconductivity is also detected on the fcc-Sn (111) surface,and the size of superconducting gap on the Sn surface is nearly the same as that on the superconducting substrate.Furthermore,phase transition occurs from fcc-Sn(111) to β-Sn(001) by keeping the sample at room temperature for a certain time.Due to the strain relaxation on the β-Sn islands,both the in-plane unit cell and out-of-plane structures distort,and the height of surface atoms varies periodically to form a universal ripple structure.