We have observed a set of broad luminescence bands between 1.07 and 0.
85 eV, in He-implanted Si annealed in vacuum. These emissions are very
similar to those of H-implanted and annealed Si, demonstrated by diff
erent groups in last years, in which H was believed to play a fundamen
tal role. A comparison between the photoluminescence of He-implanted S
i and of H-implanted Si, has allowed to conclude that the infrared pho
toluminescence of the Si:H system does not depend on H presence, but m
ust be completely ascribed to the damage produced by the bombardment o
f Si with light ions. (C) 1997 Published by Elsevier Science Ltd. All
rights reserved.