Synthesis and photoresponse of rare earth doped phosphosilicates

ABSTRACTPhosphate ceramics doped with Sm3+ and Tb3+ ions were synthesized through sol-gel process. Thin films of Tb3+ doped phosphosilicates were fabricated by spin coating of the phosphosilicate sols on SiOx/indium-tin-oxide/glass substrates. The gels synthesized by reaction of P2O5 with tetraethoxy silane (TEOS) were fired in air at a temperature range of 200°C – 900°C. The crystal structure was examined by x-ray diffractometry. Si5O(PO4)6 was the only crystalline phase. The fluorescence spectra of Sm3+ as a function of firing temperature, composition and structure of the matrices were investigated. The intensity of Sm3+ emission 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.