I want to know about the dangling bond? by which method we can find it, does its need some special type of characterization just like XRD etc... or method
i want to find dangling bond effect in AlGaN based material
thank you in advance
Dangling bonds form ''naturally'' at the boundary surface of a material as well as at the interface between two different materials grown side by side.
Danging bonds give rise to defects and more particularly to vacancies.
In order to study danging bonds and their effects, it is necessary to study the influence of related defects on a given material's or hjeterostructure's properties.
- These dangling bonds related defects play a crucial role in surface properties of a material and can even induce a fundamental change of these properties.
See for instance :
Article Hydrogen dangling bonds induce ferromagnetism in two-dimensi...
- These dangling bonds related defects play also a crucial role in heterostructure growth and properties as in the following example of MBE grown GaAs-AlAs superlattices where these defects are shown to control diffusion processes and induce growth anisotropy:
'' X‐ray diffraction study of interdiffusion and growth in (GaAs)n(AlAs)m multilayers'' by R. M. Fleming, D. B. McWhan, A. C. Gossard, W. Wiegmann, and R. A. Logan
in Journal of Applied Physics 51, 357 (1980); https://doi.org/10.1063/1.327310
- Dangling bonds related defects are controlling surface formation and reconstruction of a given material through the control of surface phenomena as adsorption. Thsi is shown in the following study :
''Structure determination of the Ge(111)−2×1-Sb surface using X-ray diffraction''
by Roelof G.van Silfhout et al. in Surface Science Volume 271, Issues 1–2, 1992, Pages 32-44
In the case of GaN, AlN and AlGaN, the situation is more complicated because of the hexagonal symmetry of these materials and related piezoelectric polarization effects at their surfaces and interfaces.
There are many papers on this topics , e.g. :
- ''Reconstructions and origin of surface states on AlN polar and nonpolar surfaces'' by M. S. Miao, A. Janotti, and C. G. Van de Walle in PHYSICAL REVIEW B 80, 155319 2009 ( DOI: 10.1103/PhysRevB.80.155319 )
and :
- ''Surface Preparation and Deposited Gate Oxides for Gallium Nitride Based Metal Oxide Semiconductor Devices''
by Rathnait D. Long * and Paul C. McIntyre in Materials 2012, 5, 1297-1335; doi:10.3390/ma5071297
Best regards,
Professor A. Kadri
Dangling bond basically is the incomplete bond in doped and undoped semiconductor material. It arises at the surface and don't participate in covalent bonding.
It is very hard to find out this bonding but you can see in VESTA file after refining your xrd data by Rietveld refinement. This can show you the unit cell of material and you can easily see the incomplete bonding i.e. dangling bond, if you considered this unit cell at the surface.
Regards
Miao, M. S., Anderson Janotti, and Chris G. Van de Walle. "Reconstructions and origin of surface states on AlN polar and nonpolar surfaces." Physical Review B 80, no. 15 (2009): 155319.
Abderrahmane Kadri Sir I fabricate nonpolar (11-20) r-plane AlGaN epilayers by MOCVD. is there any reference about this material. i read and study your provided links paper but its hard to get dangling bond for my epilayers.
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