Growth, phase and electronic structure of RbTiOPO4 crystals doped with antimony

RbTiOPO4 crystals doped with different concentrations of antimony (Sb) (5-15%) were grown by high-temperature solution method. At the bottom of the crucible, a large amount of crystalline particles and a small amount of flaky crystals were obtained. The crystalline phase, chemical composition and electronic structure of the crystals were analyzed by X-ray diffraction (XRD), electron probe microanalyzer (EPMA) and X-ray photoelectron spectroscopy (XPS). The results show that the doped crystals belong to KTP phase when the concentration of Sb is lower. When the doping concentration of Sb is up to 15%, a new phase is generated and a large amount of white flake materials are produced. From the detailed XPS spectra of P 2p, O 1s and Ti 2p3/2, we found that the binding energy difference between the O 1s and P 2p is stable for different doping concentrations: ΔBE (OP) = 398.1 eV. The binding energy difference between the O 1s and Ti 2p3/2 increases firstly and then decreases with increasing Sb content. Compared with pure RTP, the electronic structure of antimony-doped RTP crystals has changed. The ionicity of TiO bond in the crystal increases with the increase of doping concentration when Sb content is no more than 10%. Sb doping has no significant effect on the PO bond property.