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Morphology and composition of encoded segmented metal oxide nanowires

EMSL Project ID


The recent interest in one-dimensional semiconducting nanostructures is based on their possible operation as ultrasmall active elements in applications such as nanoelectronics, optoelectronics, lasers, chemical and biological sensors and energy conversion devices. Among the materials from which nanostructures have been fashioned SnO2 has received a great deal of attention primarily because of its promise in sensors and in other electronic and optoelectronic devices, but also because of its ability to form a multitude of unusual nanostructures including belts, disks and zigzags. To conform with the requirements of these varied functions, nanostructures with highly varied composition and morphology must be attainable. Several methods have been demonstrated for creating 1-D nanostructures with controllable composition and morphological variation both coaxial with and lateral to the nanostructure’s length, thereby creating nanowire superlattices with electronic and optical properties differing from the analogous bulk material. Recently, we developed a new method to control the morphology of SnO2 nanowires. This method produces segmented nanowires with segmentation that can be encoded by pulsing the flow under which these wires grow.
Objectives: 1. To further our understanding of the mechanism under which the segmented nanowires grow. What are the favorable conditions , such as pressure, temperature, flow rate, carrier gas, and pulse duration for optimal segmented wire formation? 2. Expanding the method to other metal oxides, such as In2O3 and ZnO . Is the segmentation a general phenomena, or is it specific to SnO2? Approach : Oxide nanowires (SnO2, In2O3, ZnO) will be grown inside a tube oven at 900C under flow of different carrier gasses at typical flow rates of 100sccm, at different encoding regimes. The wires, either as grown on alumina crucibles or transferred to silicone wafers/ TEM grids will be analyzed in the SEM, specifically looking for the morphology changes along the wires’ length. EDS anaylsis will be used to check for any chemical composition changes in the wires. All growth processes will be performed in USIC .

Project Details

Project type
Exploratory Research
Start Date
End Date


Principal Investigator

Andrei Kolmakov
Southern Illinois University

Team Members

Yigal Lilach
Hebrew University of Jerusalem

Alexander Laskin
Purdue University

Related Publications

Abid AD, ED Tolmachoff, DJ Phares, H Wang, Y Liu, and A Laskin. 2009. "Size Distribution and Morphology of Nascent Soot in Premixed Ethylene Flames With and Without Benzene Doping." In Proceedings of the Combustion Institute, vol. 32, pp. 681-688. Elsevier, New York. doi:10.1016/j.proci.2008.07.023