RED TO GREEN RAINBOW PHOTOLUMINESCENCE FROM UNOXIDIZED SILICON NANOCRYSTALLITES

We prepared luminescent silicon by incorporating H2O2 in the anodizing process. Under UV excitation, our samples appear reddish, orangish, y ellowish to greenish as the electrolyte-air interface at the meniscus is approached. Under high current anodization, the emission becomes br oad but unstable. The time characteristics of all the emission regions are in the range of 1-10 mu s. The results are consistent with a sign ificant reduction of crystallite sizes, and may be explained via novel Si-Si dimer surface states that are induced by quantum confinement. ( C) 1998 American Institute of Physics. [S0021-8979(98)06106-4].