Defect Induced Room Temperature Ferromagnetism in Well-Aligned ZnO Nanorods Grown on Si (100) Substrate

School of Nano and Advanced Materials Engineering, Changwon National University, Changwon, Gyeongnam, 641-773, Republic of Korea
Thin Solid Films (Impact Factor: 1.76). 09/2011; 519(23). DOI: 10.1016/j.tsf.2011.03.062


In this work, we report the fabrication of high quality single-crystalline ZnO nanorod arrays which were grown on the silicon (Si) substrate using a microwave assisted solution method. The as grown nanorods were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence (PL) and magnetization measurements. The XRD results indicated that the ZnO nanorods are well oriented with the c-axis perpendicular to the substrate and have single phase nature with the wurtzite structure. FE-SEM results showed that the length and diameter of the well aligned rods is about similar to 1 mu m and similar to 100 nm respectively, having aspect ratio of 20-30. Room-temperature PL spectrum of the as-grown ZnO nanorods reveals a near-band-edge (NBE) emission peak and defect induced green light emission. The green light emission band at similar to 583 nm might be attributed to surface oxygen vacancies or defects. Magnetization measurements show that the ZnO nanorods exhibit room temperature ferromagnetism which may result due to the presence of defects in the ZnO nanorods.

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    • "The UV emission band is usually attributed to the near-band edge emission of the wide band gap of ZnO due to the annihilation of excitons [8, 19–21]. The visible emission is the most commonly observed and is often attributed to the defect emission [22] [23] [24] [25] [26] [27]. It is known that different defects may cause different electronic structures, which will be reflected on the corresponding optical properties observed in experiments. "
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