Spectroscopic properties of CeF3 and LuF3 : Ce3+ thin films grown by molecular beam epitaxy

First results on optical properties of CeF3 and LuF3:Ce3+ thin films deposi ted by molecular beam epitaxy on both calcium fluoride and silicon substrat es are presented. For the first time, absorption spectra have been measured and analyzed, and oscillator strengths of the 4f --> 5d absorption transit ions have been deduced. Extra absorption and excitation bands at higher ene rgy have been assigned to Ce 4f --> 6s and F 2p --> Ce 5d transitions and o ne sharp band near the fundamental absorption to the exciton formation. (C) 2001 Elsevier Science B.V. All rights reserved.