in the bulk utter unncaling in forming gas but not after high tempemture ( 1100"C) anneaIs in Ar. The presence of hydrogen dmmatical[y incrcascs the broad PL band centered in the near-infmred after tinncaling Lit1100"C but htis almost no effect on the PL spectral distribution. Hydrogen is found to sclccti~cly trap in the region where Si nanocrystais are formed, consistent with a model of H ptissivatin: surfucc states tit the Si/SiO: interface that leads to enhanced PL. The thermal stabiIity of the tmppul H and the PL yield observed ufter a high temperature anneal have been studied. The hydrogen concentration and PL yield are unchanged for subsequent anneals up to 400"C. However, ubovc -IO(YCthe PL decreases tind a more complicated H chemistry is evident. Similar concentmtions of H or D ure tmpped after annealing in HJ or Dj forming gas; however, no differences in the PL yield or spcctrtil distribution tire observed, indicating that the electronic transitions resulting in luminescence are not dependent on the moss of the hydrogen species
