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ABSTRACT: The process of thermal decomposition of SiO x layers prepared by magnetron sputtering is studied with the use of photoluminescence and Auger and SIMS spectroscopies. From these measurements, we obtained the distributions of the emission properties and the chemical composition over the depth. The effect of the redistribution of silicon and oxygen over the depth is found after the high-temperature annealing which results in the formation of a Si nanocrystal. These redistributions result in the appearance of a Si-depleted region near the layer-substrate interface. The formation of a depletion layer is dependent on the excess of Si. A decrease of the silicon content over the depth of annealed layers is accompanied by a decrease of the Si nanocrystal size, as it is evidenced by the blue shift of the photoluminescence maximum. The mechanism of decomposition of SiO x and the possible reasons for the appearance of a Si-depleted region are discussed.
Semiconductor Physics, Quantum Electronics & Optoelectronics. 10/2007; 10(4):21-25.
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ABSTRACT: In this work the aging processes of magnetron-sputtered Si–SiOx structures with silicon quantum dots are investigated by photoluminescence, electronic paramagnetic resonance, infrared absorption, and Raman-scattering methods. It is observed that oxidation of the silicon dots, change in the defect concentration in the oxide matrix, and oxidation of the silicon amorphous phase occur during storage in air at room temperature. A comparison of the variation of parameters of sputtered structures and porous silicon layers caused by the aging process is made. It is shown that the rate of oxidation of silicon dots and the decrease of their sizes in sputtered structures are essentially less than that in porous silicon. It is also shown that in Si–SiOx, layers in contrast to porous silicon, the intensity and spectral position of the emission band caused by exciton recombination in Si crystallites do not change practically during aging.
Journal of Applied Physics 12/2005; 98(11):113515-113515-5. · 2.17 Impact Factor
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ABSTRACT: Photoluminescence and its temperature dependence, Raman scattering and photoluminescence excitation spectra for porous silicon, as well as their transformation during keeping in ambient air, have been investigated. The competition of different radiative channels was observed. It is shown that only one of them, that causes infrared emission band and dominates in as-prepared samples, is connected with excitonic recombination in Si nanocrystals. It is found that aging leads to an appearance of second radiative channel that causes red emission. Peculiarities of photoluminescence excitation and Raman scattering spectra, as well as of thermal quenching processes in porous silicon and the conditions for two radiative channel competitions are discussed.
Journal of Luminescence. 115:117-121.
