Luminescence properties of pure and Eu-doped SrI2 crystals purified by a “Liquinert” process and grown by vertical Bridgman method.

We have prepared high quality crystals of pure SrI 2 and Eu-doped SrI 2 by our original “Liquinert” process and investigated their luminescence properties. Under the excitation with the 193 nm light of an ArF excimer laser, which corresponds to the wavelength above the bandgap of SrI 2 bulk crystals, the pure and Eu doped SrI 2 crystals exhibit no luminescence band related to defects or impurities around 560 nm. This fact indicates that the crystals prepared by the “Liquinert” process contain lower defects and/or impurities. When the Eu-doped SrI 2 crystals are excited with the 325 nm light of a He–Cd laser, only the luminescence band due to the 5d→4f transition in the Eu 2+ ions is observed around 425 nm. The 425 nm band observed at a forward configuration exhibits the shift to the longer wavelength side and the decrease of the luminescence intensity with increasing Eu concentration. The Eu concentration dependences of the peak wavelength and luminescence intensity are simulated on the basis of a simple self-absorption model. [ABSTRACT FROM AUTHOR]