Nanoscratch Characterization of GaN Epilayers on c- and a-Axis Sapphire Substrates
<p>Abstract</p> <p>In this study, we used metal organic chemical vapor deposition to form gallium nitride (GaN) epilayers on c- and a-axis sapphire substrates and then used the nanoscratch technique and atomic force microscopy (AFM) to determine the nanotribological behavior and de...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2010-01-01
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| Series: | Nanoscale Research Letters |
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1007/s11671-010-9717-8 |
| _version_ | 1797720739937255424 |
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| author | Wen Hua-Chiang Jeng Yeau-Ren Lin Meng-Hung Chou Chang-Pin |
| author_facet | Wen Hua-Chiang Jeng Yeau-Ren Lin Meng-Hung Chou Chang-Pin |
| author_sort | Wen Hua-Chiang |
| collection | DOAJ |
| description | <p>Abstract</p> <p>In this study, we used metal organic chemical vapor deposition to form gallium nitride (GaN) epilayers on c- and a-axis sapphire substrates and then used the nanoscratch technique and atomic force microscopy (AFM) to determine the nanotribological behavior and deformation characteristics of the GaN epilayers, respectively. The AFM morphological studies revealed that pile-up phenomena occurred on both sides of the scratches formed on the GaN epilayers. It is suggested that cracking dominates in the case of GaN epilayers while ploughing during the process of scratching; the appearances of the scratched surfaces were significantly different for the GaN epilayers on the c- and a-axis sapphire substrates. In addition, compared to the c-axis substrate, we obtained higher values of the coefficient of friction (μ) and deeper penetration of the scratches on the GaN a-axis sapphire sample when we set the ramped force at 4,000 μN. This discrepancy suggests that GaN epilayers grown on c-axis sapphire have higher shear resistances than those formed on a-axis sapphire. The occurrence of pile-up events indicates that the generation and motion of individual dislocation, which we measured under the sites of critical brittle transitions of the scratch track, resulted in ductile and/or brittle properties as a result of the deformed and strain-hardened lattice structure.</p> |
| first_indexed | 2024-03-12T09:23:54Z |
| format | Article |
| id | doaj.art-1772ac3a738247aeb3449b616b47b29e |
| institution | Directory Open Access Journal |
| issn | 1931-7573 1556-276X |
| language | English |
| last_indexed | 2024-03-12T09:23:54Z |
| publishDate | 2010-01-01 |
| publisher | SpringerOpen |
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| series | Nanoscale Research Letters |
| spelling | doaj.art-1772ac3a738247aeb3449b616b47b29e2023-09-02T14:18:31ZengSpringerOpenNanoscale Research Letters1931-75731556-276X2010-01-0151118121816Nanoscratch Characterization of GaN Epilayers on c- and a-Axis Sapphire SubstratesWen Hua-ChiangJeng Yeau-RenLin Meng-HungChou Chang-Pin<p>Abstract</p> <p>In this study, we used metal organic chemical vapor deposition to form gallium nitride (GaN) epilayers on c- and a-axis sapphire substrates and then used the nanoscratch technique and atomic force microscopy (AFM) to determine the nanotribological behavior and deformation characteristics of the GaN epilayers, respectively. The AFM morphological studies revealed that pile-up phenomena occurred on both sides of the scratches formed on the GaN epilayers. It is suggested that cracking dominates in the case of GaN epilayers while ploughing during the process of scratching; the appearances of the scratched surfaces were significantly different for the GaN epilayers on the c- and a-axis sapphire substrates. In addition, compared to the c-axis substrate, we obtained higher values of the coefficient of friction (μ) and deeper penetration of the scratches on the GaN a-axis sapphire sample when we set the ramped force at 4,000 μN. This discrepancy suggests that GaN epilayers grown on c-axis sapphire have higher shear resistances than those formed on a-axis sapphire. The occurrence of pile-up events indicates that the generation and motion of individual dislocation, which we measured under the sites of critical brittle transitions of the scratch track, resulted in ductile and/or brittle properties as a result of the deformed and strain-hardened lattice structure.</p>http://dx.doi.org/10.1007/s11671-010-9717-8Gallium nitrideMetal organic chemical vapor depositionNanoscratchAtomic force microscopy |
| spellingShingle | Wen Hua-Chiang Jeng Yeau-Ren Lin Meng-Hung Chou Chang-Pin Nanoscratch Characterization of GaN Epilayers on c- and a-Axis Sapphire Substrates Nanoscale Research Letters Gallium nitride Metal organic chemical vapor deposition Nanoscratch Atomic force microscopy |
| title | Nanoscratch Characterization of GaN Epilayers on c- and a-Axis Sapphire Substrates |
| title_full | Nanoscratch Characterization of GaN Epilayers on c- and a-Axis Sapphire Substrates |
| title_fullStr | Nanoscratch Characterization of GaN Epilayers on c- and a-Axis Sapphire Substrates |
| title_full_unstemmed | Nanoscratch Characterization of GaN Epilayers on c- and a-Axis Sapphire Substrates |
| title_short | Nanoscratch Characterization of GaN Epilayers on c- and a-Axis Sapphire Substrates |
| title_sort | nanoscratch characterization of gan epilayers on c and a axis sapphire substrates |
| topic | Gallium nitride Metal organic chemical vapor deposition Nanoscratch Atomic force microscopy |
| url | http://dx.doi.org/10.1007/s11671-010-9717-8 |
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