Synthesis and Characterization on Fe-doped In2O3 Nanoparticles
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Synthesis and Characterization on Fe-doped In2O3 Nanoparticles Sandra Dussan-Devia1, Manoj K Singh1, G. L. Sharman1, R. S. Katiyar1, and C Rinaldi2 1 Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, 00931, Puerto Rico 2 Department of Chemical Engineering, University of Puerto Rico, Mayaguez, 00681-9046, Puerto Rico ABSTRACT Pure and Fe-doped In2O3 nanocrystalline powder was synthesized using a solution chemistry route based on the Sol-Gel process, which is a simple and inexpensive technique and produces long-time stable stock solutions. The X-ray diffraction patterns revealed the formation of nanocrystalline particle size with well-crystallized cubic bixbyte structure. The average crystal size was calculated from XRD patterns using Debye-Scherrer’s equation for the (222) peak and found to be 8 nm. This observation agrees well with the particle size estimated from transmission electron microscopy (TEM). The observed Raman peaks in the doped materials are shifted towards the lower frequency up to 15 cm-1 and we did not observed any additional new Raman modes with Fe doping. This clearly indicates that Fe ions are indeed occupying interstitial/substitutional sites in the host In2O3, in agreement with XPS measurements. Magnetic properties were studied using superconducting quantum interference device magnetometer (Quantum design MPMS XL-7). Preliminary magnetic measurement results suggest the incorporation of the dopants in the diamagnetic In2O3-host structure. INTRODUCTION Nanostructured Dilute Magnetic Semiconductors (DMSs) are of great technological importance due to their potential applications in spintronic and optoelectronic devices. Several oxide materials doped with transition metal ions have been reported to induce ferromagnetic behavior near or above room temperature in ZnO, TiO2 and III-V semiconductor GaN [1,2,3]. But the origin of ferromagnetism in these systems is not totally understood. In this type of nanoscale semiconductor oxides the decrease in crystal size leads to the change in their physical, chemical and optical properties. We have observed an increase in the band gap energy when the semiconductor crystallite size is in the nanometer range, this effect can be attributed to the quantum confinement of electronic wave functions. [4]. The search for new diluted magnetic semiconductors that present high solubility of the magnetic dopant ions is the goal to form thermodynamically stable magnetic semiconductors. Yoo [5,6] and co-workers reported research on ferromagnetic host semiconductor systems in (In1-xFex)2 O3-y and Cu co-doped bulk ceramic samples and thin films, synthesized by solid-state reaction method and PLD respectively. Other authors have reported room-temperature ferromagnetism which can be achieved in transition metal ions doped Indium oxide such as Ni [7,8], Mn-Fe-Cr [9,10]. Indium oxide is a transparent n-type semiconductor with a direct band-gap of about 3.6 eV in the bulk state, with cubic bixbyte structure whose lattic
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