In-situ investigation of Bi thin film condensation by surface sensitive X-ray absorption spectroscopy at cryogenic temperatures

Abstract

Reflection mode grazing incidence X-ray absorption spectroscopy at the Bi L3-edge and simultaneous electrical resistivity measurements were used to investigate the microstructure of quench condensed thin Bi metal films on float-glass substrates at temperatures from 20 K to 300 K. While thin films of 6 nm thickness appear to be amorphous after deposition at 20 K, thicker films of about 18 nm show the well-known rhombohedral structure of bulk Bi. During a subsequent heat treatment, the amorphous structure of the thin films transforms irreversibly into the crystalline form for temperatures at (42 2) K. This crystallisation is accompanied by an irreversible increase of the film resistivity by a factor of more than 2.7. The film density and roughness do not change within detection limits during the heat treatment. © 2009 IOP Publishing Ltd.