ENVIRONMENT OF ER IN EPITAXIAL CA1-XERXF2-FILMS USING LOCAL TECHNIQUES(X THIN)

We present a study of Er3+ in Ca1-xErxF2+x thin films, epitaxially gro wn by thermal sublimation of the solid solution on silicon and CaF2 su bstrates. Several techniques were used in the characterization of the films, with the aim to interpret their physical properties. Extended x -rays absorption fine structure as well as the electron spin resonance show that the films present fewer clusters than Er3+ diluted in the b ulk CaF2, confirming previous optical studies. These results show that the films are more convenient than the bulk materials to use in optic al devices. (C) 1998 American Institute of Physics. [S0021-8979(98)056 18-7]