Understanding the physical and chemical processes at the interfaces of metals and topological insulators is crucial for the development of the next generation of topological quantum devices. Here, we report the discovery of robust superconductivity in Pd/Bi2Se3 bilayers fabricated by sputtering Pd on the surface of Bi2Se3. Through transmission electron microscopy measurements, we identify that the observed interfacial superconductivity originates from the diffusion of Pd into Bi2Se3. In the diffusion region, Pd chemically reacts with Bi2Se3 and forms a layer of PdBiSe, a known superconductor with a bulk transition temperature of 1.5 K. Our work provides a method for the introduction of superconductivity into Bi2Se3, laying the foundation for the development of sophisticated Bi2Se3-based topological devices.
Keywords: Bi2Se3; topological insulator; topological superconductivity.