Title

Effect of applied magnetic field on the surface morphology, optical and electrical properties of tin oxide (SnO2) nanomaterial for meat spoilage detection

Date of Publication

2015

Document Type

Master's Thesis

Degree Name

Master of Science in Physics

Subject Categories

Physics

College

College of Science

Department/Unit

Physics

Thesis Adviser

Gil Nonato C. Santos

Defense Panel Chair

Emmanuel T. Rodulfo

Defense Panel Member

Christopher T. Que

Abstract/Summary

The study examined the effect of applied magnetic field (AMF) on the surface morphology, elemental composition, optical, and electrical properties of tin oxide (SnO2) nanomaterials. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) Analysis were used in morphology characterization. Photoluminescence characterization was also completed using Applied Spectral Imaging SD-300. The current voltage (IV) characteristics were determined using the Keithley 2400 Source Meter and Keithley 2010 multimeter, the result from which the resistivity of the sample was computed. The study also explored the gas sensing capability of the synthesized nanomaterials to meat spoilage.

The nanomaterials were produced using the Horizontal Vapor Phase Crystal Growth (HVPG) deposition method where fused quartz tubes containing 50 mg of SnO2 powder was evacuated to a base pressure of 10-6 Torr and annealed at a temperature of 1,200 ºC at growth time of 4 hours, 6 hours, and 8 hours with a ramp time of 40 minutes using a Thermolyne horizontal tube furnace. The magnetic field intensity was varied from 2500 gauss to 3100 gauss as well as the position of the permanent magnet along the tube.

In the absence of applied magnetic field (AMF), the diameters of the grown structures were found to increase with increase in growth time. With the presence of AMF, nanowire formation was favored with a more defined structure and greater density when the magnet is farther from the furnace, section 3b, and at greater intensity, 3100 gauss. A greater density of nanowire deposit at the mentioned section was also observed in longer growth time, 8 hours. On the other hand, lower magnetic field intensity, 2500 gauss, was observed to produce lower density and length of structures. The presence of the external magnetic field, along with the presence of temperature gradient, was found to be responsible for the formation of the homogenized nanowires. However, the temperature gradient has a greater influence than the presence of external magnetic field in the growth of the nanowire. EDX confirms the presence of tin oxide on the structures formed in the sections of the tube.

Abstract Format

html

Language

English

Format

Electronic

Accession Number

CDTG006545

Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

1 computer optical disc ; 4 3/4 in.

Keywords

Magnetic fields; Stannic oxide; Nanostructured materials

This document is currently not available here.

Share

COinS