Interface investigations of iron and cobalt metallized porous silicon: AES and FTIR analyses

Abstract

Porous silicon (PS) is characterized by a very large surface that is very reactive with the external environment. In this work, the chemical composition of the internal surface of both freshly anodically formed and electroplated PS with Fe and Co metals was studied. The samples were analyzed by scanning electron microscopy (SEM), Fourier transform infrared absorption spectroscopy (FTIR) and Auger electron spectroscopy (AES) combined to sputter depth profiling. Mesoporous structures with different morphologies were obtained in p-type Si(100) anodized in ethanoic hydrofluoric acid solutions. We showed that the surface of as-prepared PS is practically oxide-free and H-terminated, whereas the metal deposition process oxidizes the pore walls. Nevertheless, silicon atoms from PS surface are likely bonded to iron and cobalt ones.

Influence of alkali metallization (Li, Na and K) on photoluminescence properties of porous silicon

“…It was reported that metal-oxygen-silicon bonding is expected between 300 and 700 cm À1 wave number region [18,19]. However, no new peak has been observed in this study in this region.…”

Photoluminescence enhancement and stabilisation of porous silicon passivated by iron

“…2). Many authors [18,19] have reported that metal-oxygen-silicon bonding is expected between 300 and 700 cm À1 . So, the new peak at 460 cm À1 is due to the change in the surface bonds of PS/Fe nanocomposite and it can be attributed to (iron-oxygen)-silicon bonding.…”

Study of nanocomposite iron/porous silicon material

“…The features in spectra given by Si-O or Si-OH bonds are replaced by absorption bands related to iron oxides or iron hydroxides. For example, the shift to lower energy of Si-OH peaks is due to incorporation of the heavy metal atom into metal-silicon oxide systems, Me-O-Si bonds, and various component peaks of iron oxide bands that could be the result of formation of covalent bonds with SiO − groups appear at wavelengths lower than 1000 cm −1 [10]. Moreover, metal-silicon and as well as most of metal-oxygen (or mixed metal-oxygen-silicon) bonding are expected between 100 and 500 cm −1 and between 300 and 700 cm −1 , respectively [11].…”