An LED includes a first intermetallic layer, a first metal thin film layer, an LED chip, a substrate, a second metal thin film layer, and a second intermetallic layer. The first metal thin film layer is located on the first intermetallic layer. The LED chip is located on the first metal thin film layer. The second metal thin film layer is located on the substrate. The second intermetallic layer is located on the second metal thin film layer, and the first intermetallic layer is located on the second intermetallic layer. Materials of the first and the second metal thin film layer are selected from a group consisting of Au, Ag, Cu, and Ni. Materials of the intermetallic layers are selected from a group consisting of a Cu—In—Sn intermetallics, an Ni—In—Sn intermetallics, an Ni—Bi intermetallics, an Au—In intermetallics, an Ag—In intermetallics, an Ag—Sn intermetallics, and an Au—Bi intermetallics.