https://scholars.lib.ntu.edu.tw/handle/123456789/503350
標題: | Coalescence overgrowth of GaN nanocolumns on sapphire with patterned metal organic vapor phase epitaxy | 作者: | Tang, T.-Y. et al. Shiao, W.-Y. Lin, C.-H. Shen, K.-C. Huang, J.-J. Ting, S.-Y. Liu, T.-C. CHIH-CHUNG YANG Yao, C.-L. Yeh, J.-H. Hsu, T.-C. Chen, W.-C. Hsu, H.-C. Chen, L.-C. |
公開日期: | 2009 | 出版社: | American Institute of Physics | 卷: | 105 | 期: | 2 | 起(迄)頁: | 023501-1 - 023501-8 | 來源出版物: | Journal of Applied Physics | 摘要: | High-quality coalescence overgrowth of patterned-grown GaN nanocolumns on c -plane sapphire substrate with metal organic chemical vapor deposition is demonstrated. Although domain structures of a tens of micron scale in the overgrown layer can be identified with cathodoluminescence measurement, from atomic force microscopy (AFM) measurement, the surface roughness of the overgrown layer in an area of 5×5 μ m2 is as small as 0.411 nm, which is only one-half that of the high-quality GaN thin-film template directly grown on sapphire substrate (the control sample). Based on the AFM and depth-dependent x-ray diffraction measurements near the surface of the overgrown layer, the dislocation density is reduced to the order of 107 cm-2, which is one order of magnitude lower than that of the control sample and two to three orders of magnitude lower than those of ordinary GaN templates for fabricating light-emitting diodes. Also, the lateral domain size, reaching a level of ∼2.7 μm, becomes three times larger than the control sample. Meanwhile, the ratio of photoluminescence intensity at room temperature over that at low temperature of the overgrown sample is at least six times higher than that of the control sample. Although the strain in nanocolumns is almost completely released, a stress of ∼0.66 GPa is rebuilt when the coalescence overgrowth is implemented. © 2009 American Institute of Physics. |
URI: | https://scholars.lib.ntu.edu.tw/handle/123456789/503350 https://www.scopus.com/inward/record.uri?eid=2-s2.0-59349110463&doi=10.1063%2f1.3065527&partnerID=40&md5=b50b38e9f5cfac5c1d351c7944f86432 |
ISSN: | 00218979 | DOI: | 10.1063/1.3065527 | SDG/關鍵字: | Atomic force microscopy; Cathodoluminescence; Coalescence; Communication channels (information theory); Corundum; Crystal growth; Gallium nitride; Light; Light emission; Light emitting diodes; Luminescence; Metallorganic vapor phase epitaxy; Organic chemicals; Organic compounds; Organic light emitting diodes (OLED); Organometallics; Sapphire; Semiconducting gallium; Surface roughness; Vapors; AFM; Atomic-force microscopies; C-plane sapphire substrates; Control samples; Dislocation densities; Domain structures; GaN templates; High qualities; Lateral domains; Light emitting diode leds; Low temperatures; Metal-organic chemical vapor depositions; Metal-organic vapor phase epitaxies; Micron-scale; Nano-columns; Order of magnitudes; Photoluminescence intensities; Room temperatures; Sapphire substrates; Thin-film; Three orders of magnitudes; X-ray diffraction measurements; Gallium alloys |
顯示於: | 凝態科學研究中心 |
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