The effects of La3+ doping on luminescence properties of PbWO4 single crystal

X-ray-excited luminescence (XEL), thermoluminescence (TL), photoluminescence under excitation of UV light and X-ray photoelectron spectroscopy (XPS) measurements were conducted on PbWO4 (PWO) single crystals doped with La3+ at a series of concentration levels. With the increase of doping levels, the intensity of PWO in the XEL or the excitation-emission spectra was found to decrease accordingly, especially in the case of heavy doping. TL peaks in the range from room temperature to 200degreesC disappeared after the doping with La3+. A splitting of the La3d XPS peak in the heavy La3+-doped samples was observed and proposed to be responsible for that. At a high doping level, La 31 would occupy W-sites besides Pb-sites and thus induce a self-compensation via pairs [(La-W(3+))''' - (La-Pb(3+))(circle)] - (V-O)(circlecircle) or clusters [3(La-Pb(3+))(circle) - (La-W(3+))'''], where nonradiative recombination was previously reported to occur. The mechanism of the influence on luminescence was also discussed in this paper. (C) 2003 Elsevier Science (USA). All rights reserved.