Defect studies in as-deposited and processed nanocrystalline Si/SiO2 structures

Nanocrystalline silicon (nc-Si)/SiO2 samples formed by varying processing c onditions have been examined using electron spin resonance (ESR) and photol uminescence. Results indicate the presence of three ESR centers associated with the oxidized and annealed samples, one of which has been identified as an E' defect (O vacancy), a second as an oxygen thermal donor which is mos t important at low temperatures, and a third as a Si dangling-bond resonanc e which is more pronounced at higher temperatures. The thermal donor line s hows a strong correlation with the 1.5 eV emission exhibited by the oxidize d and annealed nc-Si samples. It is suggested that an oxide-related defect similar to that reported in oxidized porous silicon may be the source of th is optical emission. [S0163-1829(98)05547-7].