Enhancement of photoluminescence of structures with nanocrystalline silicon stimulated by low-dose irradiation with γ-ray photons

Radiation Induced Enhancement of Hydrogen Influence on Luminescent Properties of nc-Si/SiO2 Structures

“…Certain enhancement (~1.5 times) of the luminescent intensity was observed earlier [13] after low-dose (~10 4  rad) ionizing irradiation (with γ -rays) of SiO 2 films containing Si nanocrystals. Contrary to the case of porous silicon, effect in the nc-Si/SiO 2 structures was observed after radiation treatment even in inert gas or vacuum; hence, it had a different nature.…”

Influence of Radiation on the Luminescence of Silicon Nanocrystals Embedded into SiO2Film

“…The "low dose effect" was explained earlier [10] by passivation of silicon broken bonds on the surface of nc-Si inclusions with hydrogen atoms and hydroxyls, which are released in oxide matrix due to decomposition of SiH and SiOH complexes under irradiation. Data obtained here for the case of irradiation of nc-Si/SiO 2 :N structures seem to confirm such a hypothesis.…”

“…The latter is known results in growth of the fast surface states density, these states being related with silicon to broken bonds [7][8][9]. In fact, certain enhancement (∼1.5 times) of luminescent intensity was observed by us earlier [10] after low dose (∼10 4 rad) ionizing irradiation ( -ray photons) of SiO 2 films with embedded Si nanocrystals. Contrary to the case of porous silicon, this effect in nc-Si/SiO 2 structures was observed after radiation treatment even in the inert gas or in vacuum; hence, it had another nature.…”

“…Recently, the authors of [11] reported that proton irradiation (the energy 3.5 MeV and the total fluence 10 12 -10 15 cm −2 ) of nc-Si in SiO 2 multilayers leads to significant decrease of the intensity of luminescence centered near 730 nm, and in appearance of the luminescence band near ∼500 nm, assigned to radiative recombination at the radiation induced centers within a-SiO 2 matrix. Larger exposure doses (∼10 6 -10 7 rad), similarly to the case of the porous silicon, led to a partial quenching of PL of the nc-Si/SiO 2 films [10]. Investigation of just this effect to elucidate the nature of the radiation defects created under ionizing exposure of nc-Si/SiO 2 films has been done in the present paper, study of the process of radiation damage annealing being mainly attended.…”