The quenching mechanism of luminescence by heavy Sm doping in ZnS was inves
tigated by the Rutherford backscattering ion channeling (RBS/C) method. Red
luminescence around 650 nm due to the 4f intra transition of Sm3+ ion was
observed in the Sm-doped ZnS, and the emission intensity becomes maximum at
an Sm concentration of about 2 x 10(19) cm(-3). The RBS/C measurements sho
wed a much shallower dip in the angular profile of Sm yields and a shallowe
r and broader Zn-dip in the heavily Sm-doped ZnS than those in the moderate
ly Sm-doped sample. These results indicate that the quenching of the lumine
scence by heavy doping of Sm is caused by the deterioration of the structur
al quality of ZnS and the large displacement of Sm atoms from the lattice s
ites. (C) 2000 Elsevier Science B.V. All rights reserved.