Modeling the non-equilibrium process of the chemical adsorption of ammonia on GaN(0001) reconstructed surfaces based on steepest-entropy-ascent quantum thermodynamics
<p>Clearly understanding elementary growth processes that depend on surface reconstruction is essential to controlling vapor-phase epitaxy more precisely. In this study, ammonia chemical adsorption on GaN(0001) reconstructed surfaces under metalorganic vapor phase epitaxy (MOVPE) conditions (3...
| Main Authors: | , , , , |
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| Format: | Journal article |
| Language: | English |
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MDPI
2017
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| _version_ | 1797078780352659456 |
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| author | Kusaba, A Li, G Von Spakovsky, MR Kangawa, Y Kakimoto, K |
| author_facet | Kusaba, A Li, G Von Spakovsky, MR Kangawa, Y Kakimoto, K |
| author_sort | Kusaba, A |
| collection | OXFORD |
| description | <p>Clearly understanding elementary growth processes that depend on surface reconstruction is essential to controlling vapor-phase epitaxy more precisely. In this study, ammonia chemical adsorption on GaN(0001) reconstructed surfaces under metalorganic vapor phase epitaxy (MOVPE) conditions (3Ga-H and N<sub>ad</sub>-H + Ga-H on a 2 × 2 unit cell) is investigated using steepest-entropy-ascent quantum thermodynamics (SEAQT). SEAQT is a thermodynamic-ensemble based, first-principles framework that can predict the behavior of non-equilibrium processes, even those far from equilibrium where the state evolution is a combination of reversible and irreversible dynamics. SEAQT is an ideal choice to handle this problem on a first-principles basis since the chemical adsorption process starts from a highly non-equilibrium state. A result of the analysis shows that the probability of adsorption on 3Ga-H is significantly higher than that on N<sub>ad</sub>-H + Ga-H. Additionally, the growth temperature dependence of these adsorption probabilities and the temperature increase due to the heat of reaction is determined. The non-equilibrium thermodynamic modeling applied can lead to better control of the MOVPE process through the selection of preferable reconstructed surfaces. The modeling also demonstrates the efficacy of DFT-SEAQT coupling for determining detailed non-equilibrium process characteristics with a much smaller computational burden than would be entailed with mechanics-based, microscopic-mesoscopic approaches.</p> |
| first_indexed | 2024-03-07T00:36:37Z |
| format | Journal article |
| id | oxford-uuid:81a4b301-a6c0-44e9-8562-c6dc7d7d2c25 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T00:36:37Z |
| publishDate | 2017 |
| publisher | MDPI |
| record_format | dspace |
| spelling | oxford-uuid:81a4b301-a6c0-44e9-8562-c6dc7d7d2c252022-03-26T21:31:38ZModeling the non-equilibrium process of the chemical adsorption of ammonia on GaN(0001) reconstructed surfaces based on steepest-entropy-ascent quantum thermodynamicsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:81a4b301-a6c0-44e9-8562-c6dc7d7d2c25EnglishSymplectic Elements at OxfordMDPI2017Kusaba, ALi, GVon Spakovsky, MRKangawa, YKakimoto, K<p>Clearly understanding elementary growth processes that depend on surface reconstruction is essential to controlling vapor-phase epitaxy more precisely. In this study, ammonia chemical adsorption on GaN(0001) reconstructed surfaces under metalorganic vapor phase epitaxy (MOVPE) conditions (3Ga-H and N<sub>ad</sub>-H + Ga-H on a 2 × 2 unit cell) is investigated using steepest-entropy-ascent quantum thermodynamics (SEAQT). SEAQT is a thermodynamic-ensemble based, first-principles framework that can predict the behavior of non-equilibrium processes, even those far from equilibrium where the state evolution is a combination of reversible and irreversible dynamics. SEAQT is an ideal choice to handle this problem on a first-principles basis since the chemical adsorption process starts from a highly non-equilibrium state. A result of the analysis shows that the probability of adsorption on 3Ga-H is significantly higher than that on N<sub>ad</sub>-H + Ga-H. Additionally, the growth temperature dependence of these adsorption probabilities and the temperature increase due to the heat of reaction is determined. The non-equilibrium thermodynamic modeling applied can lead to better control of the MOVPE process through the selection of preferable reconstructed surfaces. The modeling also demonstrates the efficacy of DFT-SEAQT coupling for determining detailed non-equilibrium process characteristics with a much smaller computational burden than would be entailed with mechanics-based, microscopic-mesoscopic approaches.</p> |
| spellingShingle | Kusaba, A Li, G Von Spakovsky, MR Kangawa, Y Kakimoto, K Modeling the non-equilibrium process of the chemical adsorption of ammonia on GaN(0001) reconstructed surfaces based on steepest-entropy-ascent quantum thermodynamics |
| title | Modeling the non-equilibrium process of the chemical adsorption of ammonia on GaN(0001) reconstructed surfaces based on steepest-entropy-ascent quantum thermodynamics |
| title_full | Modeling the non-equilibrium process of the chemical adsorption of ammonia on GaN(0001) reconstructed surfaces based on steepest-entropy-ascent quantum thermodynamics |
| title_fullStr | Modeling the non-equilibrium process of the chemical adsorption of ammonia on GaN(0001) reconstructed surfaces based on steepest-entropy-ascent quantum thermodynamics |
| title_full_unstemmed | Modeling the non-equilibrium process of the chemical adsorption of ammonia on GaN(0001) reconstructed surfaces based on steepest-entropy-ascent quantum thermodynamics |
| title_short | Modeling the non-equilibrium process of the chemical adsorption of ammonia on GaN(0001) reconstructed surfaces based on steepest-entropy-ascent quantum thermodynamics |
| title_sort | modeling the non equilibrium process of the chemical adsorption of ammonia on gan 0001 reconstructed surfaces based on steepest entropy ascent quantum thermodynamics |
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