Er3+ doping of CaF2 layers grown by molecular beam epitaxy

Molecular beam epitaxy of CaF2 monocrystalline layers Er3+ doped up to a concentration of 5 wt % is demonstrated on CaF2 substrates. Separated effusion cells containing CaF2 and ErF3 were used. The photoluminescence spectra of the samples show emissions from centers of different symmetry identified by reference to published results obtained on CaF2:Er3+ bulk crystals. No influence of the substrate orientation—(100) or (111)—on the luminescence characteristics was observed.