Growth of Single Crystal, Oriented SnO₂ Nanocolumn Arrays by Aerosol Chemical Vapour Deposition
A single-step, template-free aerosol chemical vapor deposition (ACVD) method is demonstrated to grow well-aligned SnO2 nanocolumn arrays. The ACVD system parameters, which control thin film morphologies, were systematically explored to gain a qualitative understanding of nanocolumn growth mechanisms. Key growth variables include feed rates, substrate temperature, and deposition time. System dynamics relating synthesis variables to aerosol characteristics and processes (collision and sintering) are elucidated. By adjusting system parameters, control of the aspect ratio, height, and crystal structure of columns is demonstrated. A self-catalyzed (SnO2 particles) vapor-solid (VS) growth mechanism, whereby a vapor-particle deposition regime results in the formation of nanocrystals that act as nucleation sites for the preferential formation and growth of nanocolumns, is proposed and supported. Density functional theory (DFT) calculations indicate that the preferential orientation of thin films is a function of the system redox conditions, further supporting the proposed VS growth mechanism. When taken together, these results provide quantitative insight into the growth mechanism(s) of SnO2 nanocolumn thin films via ACVD, which is critical for engineering these, and other, nanostructured films for direct incorporation into functional devices.
K. Haddad et al., "Growth of Single Crystal, Oriented SnO₂ Nanocolumn Arrays by Aerosol Chemical Vapour Deposition," CrystEngComm, vol. 18, no. 39, pp. 7544 - 7553, Royal Society of Chemistry, Oct 2016.
The definitive version is available at https://doi.org/10.1039/c6ce01443g
Civil, Architectural and Environmental Engineering
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Article - Journal
© 2016 Royal Society of Chemistry, All rights reserved.
01 Oct 2016
This work is partially supported by the Solar Energy Research Institute for India and the United States (SERIIUS), funded jointly by the U.S. Department of Energy (Office of Science, Office of Basic Energy Sciences, and Energy Efficiency and Renewable Energy, Solar Energy Technology Program, under Subcontract DE-AC36-08GO28308 to the National Renewable Energy Laboratory, Golden, Colorado) and the Government of India, through the Department of Science and Technology under Subcontract IUSSTF/JCERDC-SERIIUS/2012. Use of the Bruker d8 X-ray diffractometer in Earth and Planetary Sciences at Washington University in St. Louis is supported by the National Science Foundation, award no. NSF EAR-1161543. This research also used the resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.