| 1. |
- Yazdi, Gholamreza R., 1966-, et al.
(author)
-
Defect-free Single Crystal AlN Nanowires by Physical Vapor Transport Growth
-
Other publication (other academic/artistic)abstract
- Growth by vapor-solid mechanism of AlN nanowires with a diameter in the range of 40-500nm and a length reaching 100 μm, resulting in a max aspect ratio of 600, is reported. Theobjects are obtained at 1750 oC and 850 mbar nitrogen pressure on 4H-SiC patternedsubstrates by sublimation epitaxy, which is a version of the physical vapor transport techniqueand provides a high growth rate. The nanowires are hexagonally shaped and perfectly alignedalong the 0001 direction with a small tilt given by the substrate vicinality. It is observed thatunder nitrogen excess a preferential growth along the c-axis of the wurtzite structure takesplace, and switches to lateral growth below some critical value of nitrogen pressure.Investigations by SEM, TEM, CL and Raman spectroscopy measurements were carried out. Itis shown that the nanowires consist of wurtzitic AlN with defect free crystal structure.Possible applications have been depicted.
|
|
| 2. |
- Yazdi, G. Reza, et al.
(author)
-
Growth of quality graphene on cubic silicon carbide
-
Other publication (other academic/artistic)abstract
- The growth of epitaxial graphene was performed on the Si-face of 4H-SiC, 6H-SiC and 3C-SiC substrates by Si sublimation of SiC in Ar atmosphere at a temperature of 2000oC. Graphene surface morphology and thickness have been evaluated using low-energy electron microscopy (LEEM) and atomic force microscopy (AFM). Large homogeneous areas of graphene monolayers (over 50x50 μm2) have been successfully grown on 3C-SiC substrates. Differences in the morphology of graphene layers, grown on different SiC polytypes, are related to a large extent to minimization of the terrace surface energy during the step bunching process. The uniformity of Si sublimation is a decisive factor for obtaining large area homogeneous graphene. It is also shown that better quality graphene is grown on 3C-SiC substrates with smoother surface, because of less pronounced step bunching and lower distribution of step heights on polished surface.
|
|
