The spatial distribution of Pb centers in a disk of porous material was measured by using a microwave scanning electron spin resonance microscope and was compared with photoluminescence images. The photoluminescence intensity was negatively correlated with the electron spin resonance intensity of Pb centers having g- = 2.0092 and g|| = 2.0021 in the high-density area, while it was positively correlated in the low-density area. The generation of Pb centers was suggested to accompany the production of radiative photoluminescence-related centers. The photoluminescence efficiency decreased because the Pb centers acted as recombination centers and led to photoluminescence quenching. Implantation of O ions also decreased the photoluminescence intensity and produced dangling bonds with g = 2.0056 and defects which were tentatively identified as being O hole centers with g1 = 2.0036, g2 = 2.0064 and g3 = 2.061.

Degradation of photoluminescence and electron paramagnetic defects in naturally oxidized or oxygen-implanted porous silicon H.Furuta, C.Yamanaka, M.Ikeya: Japanese Journal of Applied Physics - 1, 1998, 37[12A], 6446-50