PElectronic properties of electrospun tin oxide nanofibers

Abstract

Tin oxide is a binary semiconducting oxide with many applications in the development of sensors and optoelectronic devices. The recent advances in tin oxide micro/nano fibers fabrication have stimulated expectations for their applications due to their quasi-one dimensional morphology. The expectations may be limited by our ability to alter or modulate the electronic properties of the fibers. Based on our previous synthesis and characterization of electrospun tin oxide micro/nanofibers, the authors continued to investigate the electronic transport properties of single tin oxide fibers (belts) using the two probe method. Single tin oxide fibers were deposited onto silicon wafers with an oxidized surface layer of 150 nm in thickness with the electrodes for the electrical measurements made by evaporating silver over a metallic grid. I-V characteristics of single fibers were measured from 300 K down to 4 K in high vacuum with zero magnetic fields and with a transverse magnetic field that varied from -9 to 9 T. The fibers demonstrated a linear I-V characteristic in the range of -1 V and +1 V with its slope sensitive to the environment and temperature. The conductivity was found to decrease monotonically as the temperature decreases from 300 K. Above 8 K the electronic conduction mechanism corresponds to 3-dimensional Variable Range Hoping (VHR). A positive magnetoresistance of 110 % was found at 4 K and the mobility and carrier concentration for temperatures from 4 K to 15 K were on the range (0.2-1.2) cm2/V.s and (5.84×1018-6.91×1020) cm-3, respectively. © 2007 IOP Publishing Ltd.