On the structural and bandgap properties of mist-CVD-grown κ-Ga2O3 post continuous temperature annealing
We investigate the continuous annealing of orthorhombic κ-Ga2O3 films on AlN/c-plane sapphire templates grown by Mist Chemical Vapor Deposition (mist-CVD) using in situ high-temperature x-ray diffraction (HT-XRD). Increasing the annealing temperature from 400 to 1100 °C in both vacuum and ambient ai...
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| Format: | Article |
| Language: | English |
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AIP Publishing LLC
2024-11-01
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| Series: | AIP Advances |
| Online Access: | http://dx.doi.org/10.1063/5.0233281 |
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| author | Yara Banda Yanqing Jia Seong-Ho Cho Bambar Davaasuren Mohamed Ben Hassine Qingxiao Wang Dalaver H. Anjum Qiaoqiang Gan Zhenqiang Ma Si-Young Bae Tien Khee Ng Boon S. Ooi |
| author_facet | Yara Banda Yanqing Jia Seong-Ho Cho Bambar Davaasuren Mohamed Ben Hassine Qingxiao Wang Dalaver H. Anjum Qiaoqiang Gan Zhenqiang Ma Si-Young Bae Tien Khee Ng Boon S. Ooi |
| author_sort | Yara Banda |
| collection | DOAJ |
| description | We investigate the continuous annealing of orthorhombic κ-Ga2O3 films on AlN/c-plane sapphire templates grown by Mist Chemical Vapor Deposition (mist-CVD) using in situ high-temperature x-ray diffraction (HT-XRD). Increasing the annealing temperature from 400 to 1100 °C in both vacuum and ambient air reveals a phase transition onset at 825 °C. High-resolution transmission electron microscopy and XRD demonstrated that annealing within the stability window of 650 to 775 °C effectively improves the crystal quality of the κ-Ga2O3 thin film. Optical transmittance and low-loss electron energy loss spectroscopy (EELS) show the pristine film’s bandgaps to be 4.96 and 4.67 eV, respectively, with reduced bandgaps in annealed films due to increased defect density. EELS-derived optical joint density of states indicates that air-annealing fosters sub-bandgap radiative processes, while vacuum annealing suppresses them, qualitatively correlated with the observed photoluminescence intensity variations. The results of this comprehensive high-temperature annealing study offer crucial insight into the influence of annealing ambient conditions on the crystallographic properties of κ-Ga2O3 films and the associated evolution of extended sub-bandgap states. |
| format | Article |
| id | doaj-art-84e3f3e613424172908ecb19eefa85d3 |
| institution | Kabale University |
| issn | 2158-3226 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | AIP Advances |
| spelling | doaj-art-84e3f3e613424172908ecb19eefa85d32024-12-04T16:59:16ZengAIP Publishing LLCAIP Advances2158-32262024-11-011411115019115019-910.1063/5.0233281On the structural and bandgap properties of mist-CVD-grown κ-Ga2O3 post continuous temperature annealingYara Banda0Yanqing Jia1Seong-Ho Cho2Bambar Davaasuren3Mohamed Ben Hassine4Qingxiao Wang5Dalaver H. Anjum6Qiaoqiang Gan7Zhenqiang Ma8Si-Young Bae9Tien Khee Ng10Boon S. Ooi11Photonics Laboratory, Electrical and Computer Engineering, Division of Computer, Electrical and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi ArabiaPhotonics Laboratory, Electrical and Computer Engineering, Division of Computer, Electrical and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi ArabiaSemiconductor Materials Center, Korea Institute of Ceramic Engineering and Technology (KICET), Jinju 52851, Republic of KoreaImaging and Characterization Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi ArabiaImaging and Characterization Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi ArabiaImaging and Characterization Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi ArabiaImaging and Characterization Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi ArabiaSustainability and Photonics Energy Research Lab, Division of Physical Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi ArabiaDepartment of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USASemiconductor Materials Center, Korea Institute of Ceramic Engineering and Technology (KICET), Jinju 52851, Republic of KoreaPhotonics Laboratory, Electrical and Computer Engineering, Division of Computer, Electrical and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi ArabiaPhotonics Laboratory, Electrical and Computer Engineering, Division of Computer, Electrical and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi ArabiaWe investigate the continuous annealing of orthorhombic κ-Ga2O3 films on AlN/c-plane sapphire templates grown by Mist Chemical Vapor Deposition (mist-CVD) using in situ high-temperature x-ray diffraction (HT-XRD). Increasing the annealing temperature from 400 to 1100 °C in both vacuum and ambient air reveals a phase transition onset at 825 °C. High-resolution transmission electron microscopy and XRD demonstrated that annealing within the stability window of 650 to 775 °C effectively improves the crystal quality of the κ-Ga2O3 thin film. Optical transmittance and low-loss electron energy loss spectroscopy (EELS) show the pristine film’s bandgaps to be 4.96 and 4.67 eV, respectively, with reduced bandgaps in annealed films due to increased defect density. EELS-derived optical joint density of states indicates that air-annealing fosters sub-bandgap radiative processes, while vacuum annealing suppresses them, qualitatively correlated with the observed photoluminescence intensity variations. The results of this comprehensive high-temperature annealing study offer crucial insight into the influence of annealing ambient conditions on the crystallographic properties of κ-Ga2O3 films and the associated evolution of extended sub-bandgap states.http://dx.doi.org/10.1063/5.0233281 |
| spellingShingle | Yara Banda Yanqing Jia Seong-Ho Cho Bambar Davaasuren Mohamed Ben Hassine Qingxiao Wang Dalaver H. Anjum Qiaoqiang Gan Zhenqiang Ma Si-Young Bae Tien Khee Ng Boon S. Ooi On the structural and bandgap properties of mist-CVD-grown κ-Ga2O3 post continuous temperature annealing AIP Advances |
| title | On the structural and bandgap properties of mist-CVD-grown κ-Ga2O3 post continuous temperature annealing |
| title_full | On the structural and bandgap properties of mist-CVD-grown κ-Ga2O3 post continuous temperature annealing |
| title_fullStr | On the structural and bandgap properties of mist-CVD-grown κ-Ga2O3 post continuous temperature annealing |
| title_full_unstemmed | On the structural and bandgap properties of mist-CVD-grown κ-Ga2O3 post continuous temperature annealing |
| title_short | On the structural and bandgap properties of mist-CVD-grown κ-Ga2O3 post continuous temperature annealing |
| title_sort | on the structural and bandgap properties of mist cvd grown κ ga2o3 post continuous temperature annealing |
| url | http://dx.doi.org/10.1063/5.0233281 |
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