Research Article Magnetic-Field-Enhanced Morphology of Tin Oxide Nanomaterials for Gas Sensing Applications Jonathan C. Briones, Gwen Castillon, Michael P. Delmo, and Gil Nonato C. Santos Physics Department, De La Salle University, 1004 Manila, Philippines Correspondence should be addressed to Jonathan C. Briones; jonathan.briones@dlsu.edu.ph Received 9 March 2017; Accepted 3 May 2017; Published 18 June 2017 Academic Editor: Ciyuan Qiu Copyright © 2017 Jonathan C. Briones et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We studied the efect of an external magnetic feld (up to 0.31 T) on the growth of SnO 2 nanowires fabricated using the horizontal vapor phase growth (HPVG) technique. Te morphology of the nanowires was characterized by using scanning electron microscopy (SEM), and the chemical composition was characterized by energy dispersive X-ray (EDX) analysis. We found that the length of nanowires was signifcantly enhanced by the application of EMF. Te aspect ratio, as well as the density of the fabricated nanowires, increased with increasing magnetic feld intensity. Although the physics behind the morphology enhancement of the nanowires under magnetic feld is still being investigated, nevertheless, we demonstrated that the magnetic feld could be used as a key parameter to control the morphology of tin oxide nanomaterials grown via HPVG technique. Te magnetically enhanced nanowires were used in the development of a gas sensor and were found to be sensitive to hydrogen sulfde gas and the headspace gas emitted by spoiling meat. 1. Introduction Tere are tremendous interests in the fabrication of vari- ous nanomaterials with diversifed morphologies, such as nanoparticles [1] and nanowires [2, 3], because of their potential applications in electronics [1, 4, 5] and medicine [6]. Physical and chemical [4, 7] methods, such as thermal evap- oration [8], chemical vapor deposition [9], sol-gel method [10], and hydrothermal methods [8], are being used to fabricate nanomaterials. Typically, for the physical methods, temperature, pressure, and chemical addition [7] are the key parameters being controlled to modify the morphologies of nanomaterials. In this study, the parameter that was varied to control the morphology of tin oxide (SnO 2 ) nanomaterials fabricated by using our home-developed horizontal vapor phase growth (HVPG) technique [11] was the presence of an external magnetic feld. Te use of a magnetic feld (0.048 T) as an external parameter in the HVPG method was frst reported by De Mesa et al. [6] in the synthesis of iron oxide nanoparticles for glucose sensing applications which were claimed to have enhanced the superparamagnetic property of the material. No other attempts were made to fabricate nanomaterials using the HVPG technique with external magnetic feld as a controlling parameter. Nanostructured SnO 2 ofers a great potential for energy and environmental applications including gas sensing due to large surface area, low cost, and low toxicity [4]. Its gas sensing capabilities are widely reported due to its excep- tionally high sensitivity to gas reaction and adsorption. Nonetheless, much innovative science needs discovery, and new techniques must be explored in the fabrication of this type of material by exploiting strategies in the feld of mate- rials science and nanotechnology. Te use of chemical and biofunctionalized gas sensors is important in many aspects such as personal safety and security, detection and diagnosis of pollutants and poisons, health, semiconductor processing, agriculture, and automotive and aerospace industries [2, 12]. Recently, it has been shown that the HVPG deposition is successful in synthesizing nanostructured SnO 2 . However, the said technique allows the growth of many kinds of struc- tures along the length of the substrate. Tus, understanding the growth mechanism of nanomaterials in HVPG technique Hindawi Journal of Nanomaterials Volume 2017, Article ID 4396723, 11 pages https://doi.org/10.1155/2017/4396723