College of Science and Health Theses and Dissertations

Date of Award

Spring 6-14-2013

Degree Type


Degree Name

Master of Science (MS)



First Advisor

Gabriela Gonzalez-Aviles, Ph.D.

Second Advisor

Jesus Pando, Ph.D.

Third Advisor

Eric Landahal, Ph.D.


Zinc oxide is an n-type transparent conducting oxide (TCO), which is used in solar cells and optoelectronics devices. ZnO has the potential to become the future choice for a wide range of TCO commercial applications replacing the current, more expensive, and toxic indium-based materials. The isothermal grain growth of ZnO nano-powders with two different initial grain sizes and the effect of forming gas reduction on their electrical properties were studied at 900 °C. The particle size was determined using synchrotron x-ray diffraction data and scanning electron micrographs. The grain size, shape, trace impurities, and synthesis methods had an effect on the electrical performance of crystallites smaller than 300 nm. For grains larger than 300 nm, similar conductivity values were achieved regardless of the initial grain size and impurities. While grain growth modestly increased the electrical performance of ZnO, the exposure to reduction gases dramatically improved the conductivity by five orders of magnitude. Synchrotron x-ray diffraction data collected in situ at 500 °C also showed that reducing gases enhanced the grain growth of nanoparticles.

Included in

Physics Commons