Enhancing electroluminescence from Au/nanoscale Si-rich SiO2 film/p-Si by doping Al into the SiO2 film and γ-ray irradiation

Doping Al into the nanoscale Si-rich SiO2 (NSS) films subsequently annealed at temperatures lower than ∼700°C 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 ∼700°C made the EL intensities of Au/NSS/p-Si samples increase by a factor larger than 6 and the EL peaks redshift evidently. γ-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 ∼700°C under the same definite forward bias decreased in the γ-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.