Interface characterization of nickel contacts to bulk bismuth tellurium selenide

Transmission electron microscopy (TEM) characterization of nickel contacts to bulk bismuth tellurium selenide [Bi-2(Te,Se)(3)] is reported. Samples were prepared in a dual column focused ion beam/scanning electron microscope (FIB/SEM) system using a lift-out technique, with ion beam energy and exposure times carefully optimized to minimize sample damage. Diffusion of Ni into Bi-2(Te,Se)(3) was observed and the formation of a nickel telluride (NiTe) interfacial region confirmed after heat treatment at 200 degrees C. Selected area diffraction patterns provided evidence of a modified bismuth telluride-like structure at the interface, identified by analytical electron microscopy to be composed of Ni and Bi-2(Te,Se)(3). Copyright (C) 2009 John Wiley & Sons, Ltd.