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Purification of silicon powder by the formation of thin porous layer followed byphoto-thermal annealing.

Khalifa M, Hajji M, Ezzaouia H - Nanoscale Res Lett (2012)

Bottom Line: Porous silicon has been prepared using a vapor-etching based technique on a commercial silicon powder.Strong visible emission was observed in all samples.Obtained silicon powder with a thin porous layer at the surface was subjected to a photo-thermal annealing at different temperatures under oxygen atmosphere followed by a chemical treatment.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire de Photovoltaïque, Centre des Recherches et des Technologies de l'Energie (CRTEn), Technopôle de Borj-Cédria BP 95, Hammam-Lif, 2050, Tunisia. mhajji2001@yahoo.fr.

ABSTRACT
Porous silicon has been prepared using a vapor-etching based technique on a commercial silicon powder. Strong visible emission was observed in all samples. Obtained silicon powder with a thin porous layer at the surface was subjected to a photo-thermal annealing at different temperatures under oxygen atmosphere followed by a chemical treatment. Inductively coupled plasma atomic emission spectrometry results indicate that silicon purity is improved from 99.1% to 99.994% after annealing at 900°C.

No MeSH data available.


FTIR spectrum of silicon powder with a thin porous layer.
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Figure 1: FTIR spectrum of silicon powder with a thin porous layer.

Mentions: In order to study the effect of vapor etching treatment on the chemical composition of silicon surface, FTIR spectra were recorded. FTIR spectrum of the silicon powder after acid vapor-etching is depicted in Figure 1. Observed FTIR bands are located at around 600 to 750 cm−l (wagging modes), 800 to 1,000 cm−1 (bending modes), and 2,050 to 2,200 cm−1 (stretching modes) associated with Si-Hn (n ≥ 1) bondings. The band at 1,000 to 1,300 cm−l corresponds to the stretching modes of the Si-O-Si bonds in the SiOx. In this band, the peak at 1,100 cm−1 represents the Si-O-Si anti-symmetric stretches, and the peak at 1,170 cm−1 corresponds to the Si-O vibration bands [3]. A sharp absorption band at 2,200 to 2,500 cm−1 is observed, and it can be attributed to the Ox-Si-H groups [3,5,11]. The weak absorption band located at 610 to 620 cm−1 corresponds to Si-Si stretching modes [4]. The broad band from 3,050 to 3,850 cm−1 corresponds to O-H stretching modes in SiOH groups and H2O [11], and the 1,630 cm−1 band is due to O-H scissor bending vibration in water [12]. SiOH group formation is due to the reaction of SiFx with water [13,14].


Purification of silicon powder by the formation of thin porous layer followed byphoto-thermal annealing.

Khalifa M, Hajji M, Ezzaouia H - Nanoscale Res Lett (2012)

FTIR spectrum of silicon powder with a thin porous layer.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3475061&req=5

Figure 1: FTIR spectrum of silicon powder with a thin porous layer.
Mentions: In order to study the effect of vapor etching treatment on the chemical composition of silicon surface, FTIR spectra were recorded. FTIR spectrum of the silicon powder after acid vapor-etching is depicted in Figure 1. Observed FTIR bands are located at around 600 to 750 cm−l (wagging modes), 800 to 1,000 cm−1 (bending modes), and 2,050 to 2,200 cm−1 (stretching modes) associated with Si-Hn (n ≥ 1) bondings. The band at 1,000 to 1,300 cm−l corresponds to the stretching modes of the Si-O-Si bonds in the SiOx. In this band, the peak at 1,100 cm−1 represents the Si-O-Si anti-symmetric stretches, and the peak at 1,170 cm−1 corresponds to the Si-O vibration bands [3]. A sharp absorption band at 2,200 to 2,500 cm−1 is observed, and it can be attributed to the Ox-Si-H groups [3,5,11]. The weak absorption band located at 610 to 620 cm−1 corresponds to Si-Si stretching modes [4]. The broad band from 3,050 to 3,850 cm−1 corresponds to O-H stretching modes in SiOH groups and H2O [11], and the 1,630 cm−1 band is due to O-H scissor bending vibration in water [12]. SiOH group formation is due to the reaction of SiFx with water [13,14].

Bottom Line: Porous silicon has been prepared using a vapor-etching based technique on a commercial silicon powder.Strong visible emission was observed in all samples.Obtained silicon powder with a thin porous layer at the surface was subjected to a photo-thermal annealing at different temperatures under oxygen atmosphere followed by a chemical treatment.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire de Photovoltaïque, Centre des Recherches et des Technologies de l'Energie (CRTEn), Technopôle de Borj-Cédria BP 95, Hammam-Lif, 2050, Tunisia. mhajji2001@yahoo.fr.

ABSTRACT
Porous silicon has been prepared using a vapor-etching based technique on a commercial silicon powder. Strong visible emission was observed in all samples. Obtained silicon powder with a thin porous layer at the surface was subjected to a photo-thermal annealing at different temperatures under oxygen atmosphere followed by a chemical treatment. Inductively coupled plasma atomic emission spectrometry results indicate that silicon purity is improved from 99.1% to 99.994% after annealing at 900°C.

No MeSH data available.