Synthesis and photoresponse of rare earth doped phosphosilicates

摘要

Phosphate ceramics doped with Sm~(3+) and Tb~(3+) ions were sytnhesized through sil-gel process. Thin films of Tb~(3+) doped phosphosilicates were fabricated by spin coating of the phosphosilicate sols on SiO_x/indium-tin-oxide/glass substrates. The gels synthesized by reaction of P_2O_5 with tetraethoxy silane (TEOS) were fired in air at a temperature range of 200 deg C-900 deg C. The crystal structure was examined by x-ray diffractometry. Si_5O(PO_4)_6 was the only crystalline phase. The fluorescence spectra of Sm~(3+) as a function of firing temperature, composition and structure of the matrices were investigated. The intensity of Sm~(3+) enission increased with increasing firing temperatures and greater proportion of phosphorus. The photocurrent of the films at 355 nm laser excitation was observed. The photoresponse as a function of laser energy was linear and showed no sign of saturation. The films exhibited stable photoresponse under a high number of laser shots.