Tchernycheva, M and Sartel, C and Cirlin, G. E. and Travers, L and Patriarche, G and Harmand, J. C. and Dang, Le. Si. and Renard, J and Gayral, B and Nevou, L and Julien, F (2007) Growth of GaN free-standing nanowires by plasma-assisted molecular beam epitaxy: structural and optical characterization. Nanotechnology, 18 (38). 385306 (7pp).
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Official URL: http://stacks.iop.org/0957-4484/18/385306
This paper reports on the growth, structural and optical properties of GaN free-stranding nanowires synthesized in catalyst-free mode on Si(111) substrate by plasma-assisted molecular beam epitaxy. Cylindrical nanowires with a hexagonal cross-section defined by <br />10<br />bar 10<br /> planes and diameters down to 20~nm were observed. The nanowire length increases as a function of their diameter, following the Gibbs-Thomson expression. The growth rate in the lateral direction was studied using thin AlN marker layers showing that the lateral over axial growth rate ratio can be tuned from [?]1% to [?]10% by changing the III/V flux ratio, with the lateral growth remaining homogeneous along the NW axis. Nanowire ensembles showed a strong near band edge photoluminescence up to room temperature. Low-temperature micro-photoluminescence from a single wire is peaked at 3.478~eV with broadening of 6-10~meV. This emission is similar to the luminescence of nanowire ensembles, which demonstrates strain homogeneity from wire to wire. The optical properties along the wire axis probed by micro-cathodoluminescence were found to be uniform, with no evidence of a higher defect density in the bottom part of the nanowires next to the Si substrate.
|Deposited By:||Prof. Alexey Ivanov|
|Deposited On:||16 Mar 2009 10:42|
|Last Modified:||27 Mar 2009 17:55|
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