Growth and Characterization of Iron Oxide Nanocrystalline Thin Films via Sol-Gel Dip Coating Method

Abstract

In this paper, iron (III) oxide thin films are deposited on glass substrate via sol-gel dip coating by increasing withdrawal speeds in the range 100-250 mms <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> . Prepared thin films were characterized by UV-VIS spectrophotometer, spectroscopic ellipsometry (SE), X-ray diffraction (XRD), scanning electron microscope (SEM), vibrating sample magnetometer (VSM) and Fourier transform infrared (FTIR) spectroscopy. UV-VIS spectrum and SE show decrease in bandgap energy from 2.8 to 1.6 eV with increased withdrawal speed. FTIR results indicate formation of α-Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (hematite) phase of iron oxide with preferred orientation along (104) plane. From SEM studies, it is observed that the developed α-Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> films are nanocrystalline with small grain size. The surface of α-Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> films is smooth and homogenous, which also supports the XRD results. VSM results show that α-Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> thin films have ferromagnetic behavior.