| Autor: |
Kim, C. C., Je, J. H., Ruterana, P., Degave, F., Nouet, G., Yi, M. S., Noh, D. Y., Hwu, Y. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 4/1/2002, Vol. 91 Issue 7, p4233, 5p, 4 Black and White Photographs, 2 Graphs |
| Abstrakt: |
We investigated the structural evolution of GaN nucleation layers in the initial growth stages on commercial c-plane sapphires with atomic steps at the surface, using field-emission scanning electron microscopy, synchrotron x-ray scattering, and high-resolution electron microscopy. GaN nucleates into islands preferentially on the atomic steps. The initial small islands of 25 Å high have well-ordered cubic sequences and nearly coherent interfacial structures with a large compressive strain of ∼10%. As the islands grow to 50 Å high, the strain is drastically reduced, to less than 1%, by generating misfit dislocations at the interface and forming the six-to-seven matched interfacial structure. Interestingly, stacking faults are developed from the GaN/sapphire interface, which induces a cubic-hexagonal transformation. The changes in the stacking order during the initial growth are investigated quantitatively. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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