IR absorption analysis of oxidation behaviors of nano-composite phases with β-FeSi₂ nanocrystals and Si

Abstract

We have investigated oxidation behaviors of nano-composite phase with -FeSi2 nanocrystals (-NCs) and Si on Si substrates. IR absorption measurements revealed that only oxidation of Si into SiO2 proceeded in the nano-composite phase. This fact is very important for realization of a novel composite phase with -NCs and SiO2, which may contribute to enhancement of light emission and to prevent a large thermal quenching of light emission observed in the composite phase with -NCs and Si.

Analysis of oxidation behavior in nanocrystal β-FeSi₂/Si composites by rutherford backscattering spectrometry and computation of diffusion flux

“…Nakamura et al have reported synthesis of nanocrystal -FeSi2 (NC-) embedded in SiO2 by using oxidation of samples in air, and they succeeded in observation of evident photoluminescence at 250 K [3]. Moreover, Morita et al [4] have reported time dependent growth of SiO2 in oxidation of -FeSi2/Si, and they found no structural and quantitative changes of NC- by using infrared absorption (IRA) measurements, and pointed that selective oxidation took place in the sample. These reports indicate that the oxidation process is effective to synthesize -FeSi2/SiO2 heterojunction with enough large band offsets for electrons and holes even above room temperature from the -FeSi2/Si heterojunction.…”