Katsu Tanaka

Photoluminescence of SrGa2S4:Mn Phosphors

The photoluminescence (PL) properties of SrGa2S4:Mn phosphor are first reported. The PL spectrum had a peak at 530 nm with a full-width-half-maximum (FWHM) of 53 nm. The luminescence was green, with color coordinates of x=0.26 and y=0.56. Thermal quenching was also measured. The PL was due to the 3d-3d transition in the 3d configuration of the Mn ion. The density of states (DOS) of each element in this phosphor was calculated with a first-principles simulation.

Changes in photoluminescence of SrS:Ce induced by synchrotron radiation

The effect of x-ray irradiation on the photoluminescence (PL) of SrS:Ce was investigated using synchrotron radiation. SrS films deposited by molecular-beam epitaxy were irradiated by x-ray pulses having an energy of 8.0 keV or 14.5 keV for duration of 17 to 50 ms. PL measurements showed that both the enhancement and deterioration of PL characteristics could be achieved by choosing a combination of shot numbers of x-ray pulses and intervals between pulses. It was found that the enhancement of PL intensity was more remarkable for x-rays of 14.5 keV than for ones of 8.0 keV. The effects of this x-ray irradiation were discussed in terms of x-ray-induced nonthermal atomic movements and thermal annealing by the heat resulting from x-ray absorption.