Chaiyawat Kaewmeechai, Jack Strand, Alexander Shluger
{"title":"Role of local structure in the optical and electronic properties of oxygen vacancies in different crystal phases of Ga2O3","authors":"Chaiyawat Kaewmeechai, Jack Strand, Alexander Shluger","doi":"10.1103/physrevmaterials.8.094603","DOIUrl":null,"url":null,"abstract":"We investigate the structural, electronic, and optical properties of oxygen vacancies (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi mathvariant=\"normal\">V</mi><mi mathvariant=\"normal\">O</mi></msub></math>) in crystalline <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>α</mi><mo>,</mo><mo> </mo><mi>β</mi></math>, and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>ε</mi><mtext>−</mtext><msub><mi>Ga</mi><mn>2</mn></msub><msub><mi mathvariant=\"normal\">O</mi><mn>3</mn></msub></mrow></math> using density functional theory (DFT) calculations with the PBE0-TC-LRC functional. Our results reveal that the charge transition levels (CTLs) associated with <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi mathvariant=\"normal\">V</mi><mi mathvariant=\"normal\">O</mi></msub></math> exhibit significant variations depending on the crystal phase and the coordination environment of surrounding atoms. In particular, <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi mathvariant=\"normal\">V</mi><mi mathvariant=\"normal\">O</mi></msub><mi mathvariant=\"normal\">s</mi></mrow></math> surrounded by tetrahedral Ga atoms (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>T</mi><mtext>-Ga</mtext></mrow></math>) exhibit deeper CTLs compared to those surrounded by octahedral Ga atoms (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>O</mi><mtext>-Ga</mtext></mrow></math>). We also observe distinct atomic relaxations, with larger displacements of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>T</mi><mtext>-Ga</mtext></mrow></math> atoms compared to <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>O</mi><mtext>-Ga</mtext></mrow></math> atoms in the vicinity of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi mathvariant=\"normal\">V</mi><mi mathvariant=\"normal\">O</mi></msub><mi mathvariant=\"normal\">s</mi></mrow></math>. Using linear-response time-dependent DFT, we investigate the optical transitions of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi mathvariant=\"normal\">V</mi><mi mathvariant=\"normal\">O</mi></msub></math> and identify two distinct types of transitions: defect state to conduction band state and valence band to defect state. These results can be used to better understand the optical properties of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi mathvariant=\"normal\">V</mi><mi mathvariant=\"normal\">O</mi></msub></math> defects in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>Ga</mi><mn>2</mn></msub><msub><mi mathvariant=\"normal\">O</mi><mn>3</mn></msub></mrow></math> films.","PeriodicalId":20545,"journal":{"name":"Physical Review Materials","volume":null,"pages":null},"PeriodicalIF":3.1000,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physical Review Materials","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.1103/physrevmaterials.8.094603","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
We investigate the structural, electronic, and optical properties of oxygen vacancies () in crystalline , and using density functional theory (DFT) calculations with the PBE0-TC-LRC functional. Our results reveal that the charge transition levels (CTLs) associated with exhibit significant variations depending on the crystal phase and the coordination environment of surrounding atoms. In particular, surrounded by tetrahedral Ga atoms () exhibit deeper CTLs compared to those surrounded by octahedral Ga atoms (). We also observe distinct atomic relaxations, with larger displacements of atoms compared to atoms in the vicinity of . Using linear-response time-dependent DFT, we investigate the optical transitions of and identify two distinct types of transitions: defect state to conduction band state and valence band to defect state. These results can be used to better understand the optical properties of defects in films.
我们使用 PBE0-TC-LRC 函数进行密度泛函理论(DFT)计算,研究了晶体 α、β 和 ε-Ga2O3 中氧空位(VO)的结构、电子和光学性质。我们的研究结果表明,与 VO 相关的电荷转移水平(CTLs)会因晶体相和周围原子的配位环境而发生显著变化。特别是,与被八面体镓原子(O-Ga)包围的 VO 相比,被四面体镓原子(T-Ga)包围的 VO 显示出更深的 CTL。我们还观察到不同的原子弛豫,与 VO 附近的 O-Ga 原子相比,T-Ga 原子的位移更大。利用线性响应时间相关 DFT,我们研究了 VO 的光学跃迁,并确定了两种不同类型的跃迁:缺陷态到传导带态和价带到缺陷态。这些结果可用于更好地理解 Ga2O3 薄膜中 VO 缺陷的光学特性。
期刊介绍:
Physical Review Materials is a new broad-scope international journal for the multidisciplinary community engaged in research on materials. It is intended to fill a gap in the family of existing Physical Review journals that publish materials research. This field has grown rapidly in recent years and is increasingly being carried out in a way that transcends conventional subject boundaries. The journal was created to provide a common publication and reference source to the expanding community of physicists, materials scientists, chemists, engineers, and researchers in related disciplines that carry out high-quality original research in materials. It will share the same commitment to the high quality expected of all APS publications.