Synthesis and characterization of β-phase iron silicide nano-particles by chemical reduction

• β-FeSi2 nano-particle was synthesized by reducing with Mg and by diluting with MgO.
• XRD profile shows the iron di-silicide phase to be semiconducting β-FeSi2.
• HRTEM and FESEM images indicate the β-FeSi2average particle size to be 60–70 nm.
• Absorption, reflectance and PL spectroscopy show band gap to be direct 0.87 eV.
• Nano-β-FeSi2is p-type with hole density of 4.38 × 1018 cm−3 and mobility 8.9 cm2/V s.

Nano-particles of β-FeSi2 have been synthesized by chemical reduction of a glassy phase of [Fe2O3, 4SiO2] by Mg-metal where MgO is used as diluent to prevent the agglomeration of nano crystallites into micro-particles and also act as a negative catalyst for the formation of other phases. The sample is characterized by XRD, FESEM, HRTEM, EDX, ultra-violet-visible-infrared and PL spectroscopy and electronic properties have been investigated by Hall measurement. XRD profile shows that the synthesized powder consists of purely β-FeSi2 semiconducting phase. The average crystallite size of β-FeSi2 is determined to be around 65.4 nm from XRD peaks as well as from FESEM also. The optical absorption and PL spectroscopy shows that synthesized β-FeSi2 phase is a direct band gap semiconductor with a value of 0.87 eV. Hall measurements show that β-FeSi2 nano-particles is p-type with hole concentration of 4.38 × 1018 cm−3 and average hole mobility of 8.9 cm2/V s at 300 K.

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