Absorption Mechanisms of Silicon Nanocrystals in Cosputtered Silicon-Rich-Silicon Oxide Films

Optical properties of silicon-rich–silicon oxide (SRSO) films have been investigated by emission and absorption spectroscopies in the broad spectral range. The impact of the different hydrogen partial pressure of the sputtering method on the absorption properties of SRSO films has been described and commented on. For all samples, a strong and complex emission band, centered at ~1.6 eV, has been observed. It has been shown that the most dominant absorption transition, centered at ~4.0 eV, is related to the direct absorption in Si nanocrystals and depends on their size. Moreover, no evidence of a quasidirect absorption band was identified.

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