Strain relaxation due to V-pit formation in In[sub x]Ga[sub 1−x]N∕GaN epilayers grown on sapphire
Strain relaxation in semiconductor heterostructures generally occurs through the motion of dislocations that generates misfit dislocations above a critical thickness. However, majority of the threading dislocations in GaN-related materials have no driving force to glide, and those with a driving for...
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2005
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| Online Access: | http://shdl.mmu.edu.my/2177/ |
| _version_ | 1848789984964771840 |
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| author | Song, T. L. |
| author_facet | Song, T. L. |
| author_sort | Song, T. L. |
| building | MMU Institutional Repository |
| collection | Online Access |
| description | Strain relaxation in semiconductor heterostructures generally occurs through the motion of dislocations that generates misfit dislocations above a critical thickness. However, majority of the threading dislocations in GaN-related materials have no driving force to glide, and those with a driving force are kinetically impeded even at a temperature of 1000 degrees C. In spite of this, the strain in InxGa1-xN/GaN epilayers grown on c-plane sapphire substrates was observed to decrease as the InxGa1-xN layer becomes thicker. We have explored the possibility of V-pit formation at terminated dislocations as the predominant relaxation mechanism in highly mismatched systems such as InxGa1-xN/GaN. We demonstrate that a driving force exists to nucleate V pits for strain relief. The formation of V pits was modeled through the energy balance between the strain energy in the InxGa1-xN epilayer, the destruction of dislocation energy to form V pits and the strain that is relieved due to the formation of edges during the process of nucleating V pits in thermal equilibrium. V-pit formation and growth lead to strain relief as the film becomes thicker. The model illustrates many features that correlate reasonably well with experimental observations; the most significant trends are a rise in V-pit density and a decrease in strain with increasing layer thickness. (c) 2005 American Institute of Physics. |
| first_indexed | 2025-11-14T18:05:25Z |
| format | Article |
| id | mmu-2177 |
| institution | Multimedia University |
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| last_indexed | 2025-11-14T18:05:25Z |
| publishDate | 2005 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | mmu-21772011-09-12T06:24:34Z http://shdl.mmu.edu.my/2177/ Strain relaxation due to V-pit formation in In[sub x]Ga[sub 1−x]N∕GaN epilayers grown on sapphire Song, T. L. QC Physics Strain relaxation in semiconductor heterostructures generally occurs through the motion of dislocations that generates misfit dislocations above a critical thickness. However, majority of the threading dislocations in GaN-related materials have no driving force to glide, and those with a driving force are kinetically impeded even at a temperature of 1000 degrees C. In spite of this, the strain in InxGa1-xN/GaN epilayers grown on c-plane sapphire substrates was observed to decrease as the InxGa1-xN layer becomes thicker. We have explored the possibility of V-pit formation at terminated dislocations as the predominant relaxation mechanism in highly mismatched systems such as InxGa1-xN/GaN. We demonstrate that a driving force exists to nucleate V pits for strain relief. The formation of V pits was modeled through the energy balance between the strain energy in the InxGa1-xN epilayer, the destruction of dislocation energy to form V pits and the strain that is relieved due to the formation of edges during the process of nucleating V pits in thermal equilibrium. V-pit formation and growth lead to strain relief as the film becomes thicker. The model illustrates many features that correlate reasonably well with experimental observations; the most significant trends are a rise in V-pit density and a decrease in strain with increasing layer thickness. (c) 2005 American Institute of Physics. 2005-10 Article NonPeerReviewed Song, T. L. (2005) Strain relaxation due to V-pit formation in In[sub x]Ga[sub 1−x]N∕GaN epilayers grown on sapphire. Journal of Applied Physics, 98 (8). 084906. ISSN 00218979 http://dx.doi.org/10.1063/1.2108148 doi:10.1063/1.2108148 doi:10.1063/1.2108148 |
| spellingShingle | QC Physics Song, T. L. Strain relaxation due to V-pit formation in In[sub x]Ga[sub 1−x]N∕GaN epilayers grown on sapphire |
| title | Strain relaxation due to V-pit formation in In[sub x]Ga[sub 1−x]N∕GaN epilayers grown on sapphire |
| title_full | Strain relaxation due to V-pit formation in In[sub x]Ga[sub 1−x]N∕GaN epilayers grown on sapphire |
| title_fullStr | Strain relaxation due to V-pit formation in In[sub x]Ga[sub 1−x]N∕GaN epilayers grown on sapphire |
| title_full_unstemmed | Strain relaxation due to V-pit formation in In[sub x]Ga[sub 1−x]N∕GaN epilayers grown on sapphire |
| title_short | Strain relaxation due to V-pit formation in In[sub x]Ga[sub 1−x]N∕GaN epilayers grown on sapphire |
| title_sort | strain relaxation due to v-pit formation in in[sub x]ga[sub 1−x]n∕gan epilayers grown on sapphire |
| topic | QC Physics |
| url | http://shdl.mmu.edu.my/2177/ http://shdl.mmu.edu.my/2177/ http://shdl.mmu.edu.my/2177/ |