Abstract: An epitaxial wafer is disclosed. The epitaxial wafer includes a substrate; and a stack structure disposed on the substrate, wherein the stack structure includes first and second layers alternately stacked on top of each other, wherein the first layer is made of a compound represented by one selected from a group consisting of following Chemical Formulas 1-1 to 1-5, wherein the second layer is made of a compound represented by a following Chemical Formula 2: Si1-xGex(m?x?1.0)??[Chemical Formula 1-1] Si1-x-yGexBy(m?x<1.0,0<y?0.4,0.2<x+y?1.0)??[Chemical Formula 1-2] Si1-x-zGexPz(m?x<1.0,0<z?0.4,0.2<x+z?1.0)??[Chemical Formula 1-3] Si1-x-zGexCz(m?x<1.0,0<z?0.4,0.2<x+z?1.0)??[Chemical Formula 1-4] Si1-x-y-zGexByPz(0.2<x<1.0,0<y?0.4,0<z?0.4,0.2<x+y+z?1.

Abstract: A method for formatting a storage medium. The method includes saving management information associated with data that is to be protected from the formatting, the management information indicating where the data to be protected is stored, formatting a management information area of the storage medium where the management information is stored, and recovering the saved management information to the management information area of the storage medium such that the data to be protected is accessible.

Abstract: A method for formatting a storage medium. The method includes saving management information associated with data that is to be protected from the formatting, the management information indicating where the data to be protected is stored, formatting a management information area of the storage medium where the management information is stored, and recovering the saved management information to the management information area of the storage medium such that the data to be protected is accessible.