Abstract
ZnO quantum disks are found to form on the top surface of a thick ZnO epilayer as a result of a morphology transition occurring during the growth of ZnO single-crystal thin films on c-plane sapphire using plasma-assisted molecular beam epitaxy. These disks manifest themselves as triangular pyramids and organize themselves to conform to the six-fold symmetry of the ZnO epilayer underneath with the base edges along <1100> and side facets of {1 2 1 6}. Atomic-force microscopy measurements show a size distribution with base width centered at 140 and 24 nm height, the height/width ratio remaining constant due to the formation of special facets. Cathodoluminescence studies reveal a strong near-bandgap emission from the regions with a high density of pyramids.
Original language | English |
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Pages (from-to) | 269-273 |
Number of pages | 5 |
Journal | Journal of Crystal Growth |
Volume | 184-185 |
DOIs | |
Publication status | Published - 2 Feb 1998 |
Externally published | Yes |
Keywords
- growth
- MBE
- morphology
- pyramid
- sapphire
- ZnO