Temperature-dependent growth of pulsed-laser-deposited bismuth thin films on glass substrates

Bismuth thin films were grown by pulsed-laser deposition on glass substrates with the substrate temperature from -40 degrees C to 200 degrees C. The structure of the films was characterized by X-ray diffraction. The surface morphology was studied by atomic force microscopy and X-ray reflectivity. The electrical properties of the films were probed by Hall and van der Pauw measurements. We observed changes in the orientation, grain size and roughness of the bismuth films as a function of the substrate temperature. In particular, at -30 degrees C, the surface roughness was drastically reduced, leading to very smooth bismuth films with highly (111)-preferred orientation. Furthermore, the preferred orientation disappeared at around -40 degrees C. (c) 2007 Elsevier B.V. All rights reserved.