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Doping Al into the nanoscale Si-rich SiO2 (NSS) films subsequently annealed at temperatures lower than similar to 700 degreesC made the EL intensity of Au/NSS/p-Si samples increase by a factor of 4-6, but did not change its EL peak wavelength. Doping Al into NSS films subsequently annealed at temperatures higher than similar to 700 degreesC made the EL intensities of Au/NSS/p-Si samples increase by a factor larger than 6 and the EL peaks redshift evidently, gamma -ray irradiation has very similar effects in increasing and redshifting the EL spectra of Au/NSS/p-Si. The currents of Au/NSS/p-Si samples with NSS/p-Si annealed at various temperatures under a definite forward bias were invariant or increased in the gamma ray irradiation process. However, the currents of Au/NSS:Al/p-Si samples with NSS:Al/p-Si annealed at temperatures smaller than similar to 700 degreesC under the same definite forward bias decreased in the gamma -ray irradiation process. The experimental facts can be interpreted qualitatively if the main origin of EL is attributed to defects and/or impurities in the NSS films. (C) 2001 Elsevier Science B.V. All rights reserved.