CHARACTERIZATION OF ZNWO4 - FE SINGLE-CRYSTALS BY OPTICAL AND SCANNING ELECTRON-MICROSCOPIC METHODS

The effect of iron dopant incorporation and certain transient growth processes on the defect formation in Czochralski-grown ZnWO4 single crystals were studied by using optical and scanning electron microscopic imaging methods as well as energy dispersive X-ray and cathodoluminescence spectroscopies. It was found that, the iron dopants in the crystals decrease the luminescence intensities, increase the half-widths of the emission bands and produce secondary peaks at 460, 515, 530 and 565 nm besides the intrinsic one detected between 480 and 503 nm at different sample temperatures. In the grown-in defect formation the Fe dopant seems to play only a minor role. The iron segregation was detected only on microdefects and at high dopant concentrations.