Analysis of Structural Transitions in Magnetron Sputtered Bi₄Se₃Films

Recently, bismuth chalcogenides have been of interest as topological insulators with uses in spintronic and other devices. Bi₄Se₃ presents a topologically insulating material which contains a native heterostructure of Bi₂Se₃ and Bi₂ layers, each with its own topological state. In spite of these valuable properties, the growth of Bi₄Se₃ via magnetron sputtering remains less studied. This study elaborates the properties of Bi₄Se₃ films grown in a magnetron sputtering system with an external magnetic field. Films were grown with varying deposition temperatures, external field orientations, and annealing procedures. Films were characterized using X-ray Diffraction and Electron Back Scatter Diffraction. The deposition temperature played a central role in determining film structure, and a transition from amorphous to polycrystalline to a primarily basally-oriented film occurred as temperature varied. Analysis of X-ray diffraction revealed clear variation in microstructure with external field orientation, and an increase in film ordering with annealing.