Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8035809 | Thin Solid Films | 2013 | 4 Pages |
Abstract
The microstructures of the P-GaN (250 nm)/GaN cap (~ 35 nm)/7 pairs of InGaN/GaN MQWs (multi-quantum wells)/n-GaN (3 μm)/HT (high temperature)-GaN (3 μm)/LT (low temperature)-GaN buffer (5 nm) on c-plane convex patterned sapphire substrate were analyzed using transmission electron microscopy (TEM). High density of dislocations in the LT-GaN buffer layer at both flat and convex patterned regions was observed to form. At the flat region, some of high dislocations formed at LT-GaN buffer grew over, bended to from stair-like dislocations extended along the edge of the convex pattern and then transformed to TDs (threading dislocations) extending through the InGaN/GaN epitaxial layers. However, few TDs reached the top of the epitaxial layers. Quantitative analysis revealed that the dislocation density has been drastically reduced to ~ 106 cmâ 2, reducing formation of V-defects at the 7 pairs of multi-quantum-wells near the surface.
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Physical Sciences and Engineering
Materials Science
Nanotechnology
Authors
Zhixin Wan, Yinsheng He, Cheljong Choi, Eunkyung Suh, Young Moon Yu, Sam-Nyung Yi, Hyung-Soo Ahn, Min Yang, Hyo-Jong Lee, Keesam Shin,