A method of more accurate phase encoding of phase offset vibrators used in simultaneous-multiple-sourcing 3D seismic mapping. The internal compression member includes a compression mechanism coupled to the moveable sidewall, and moves the movable sidewall from the first position to the second position. In a method for fabricating the heterojunction solar cell, the semiconductor A and the semiconductor B are lattice-matched to each other with a mismatch ratio of less than 1% respectively, and the semiconductor A is made of p-type silicon with a p-type germanium layer formed on the surface thereof, and n-type GaP is formed after removing an oxide film by removing the germanium layer.