Strukturelle und optische Charakterisierung von $\beta$-FeSi$_{2}$ - Si - Heterostrukturen

Schuller, Bernd Thomas

Dissertation / PhD Thesis/Book

Strukturelle und optische Charakterisierung von $\beta$-FeSi$_{2}$ - Si - Heterostrukturen

Schuller, B. T. (Corresponding author)FZJ*

2003
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Jülich : Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag, Berichte des Forschungszentrums Jülich 3986, VII, 92 p. (2003) = Aachen, Techn. Hochsch., Diss., 2002

Please use a persistent id in citations: http://hdl.handle.net/2128/272

Report No.: Juel-3986

Abstract: Semiconducting iron disilicide $\beta$-FeSi$_{2}$ is a promising material for possible applications in silicon-based optoelectronics. The bandgap of iron disilicide has a value of about 0.8 eV (1.5$\mu$m), which is of enormous interest for fibre-based communications. Recently, iron disilicide precipitates in a silicon matrix have been investigated intensively, since these structures Show good luminescence at low temperatures. However, it is still a matter of debate whether the emission is due to recombination in the silicide, or whether it originates in silicon defects. Furthermore, an interesting question is the nature of the silicide bandgap in these precipitates. In this work, iron disilicide precipitates have been fabricated by ion Implantation and subsequent annealing. This resulted in precipitates having linear dimensions of 50-100 nm in a silicon matrix. These were characterised structurally by transmission electron microscopy, Raman spectroscopy and Rutherford backscattering. Optical characterisation was done by photoluminescence spectroscopy (PL). The results of the structural investigations show that the iron disilicide precipitates are Single crystal, and basically unstrained. The lattice mismatch between silicide and the silicon matrix is compensated by misfit dislocations in the silicon. At low temperatures, the Samples Show good luminesence, the efficiency has been estimated at 0.1%. The PL intensity decreases rapidly with increasing temperature, at room temperature the PL is hard to detect. Time resolved luminescence measurements at the wavelength of the main peak (1.5 $\mu$m) show a decay time of 4$\mu$s at a temperature of 10K. The results of the luminescence measurements can be explained either by recombination at silicon defects of by an indirect transition within the silicide. In view of the long lifetime and low efficiency of the luminescence, a direct transition within the silicide can be ruled out.

Note: Record converted from VDB: 12.11.2012
Note: Aachen, Techn. Hochsch., Diss., 2002

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