AI 中文总结
本研究结合STEM技术与模拟方法，探究不同取向Ga$_{2}$O$_{3}$衬底的NiO/Ga$_{2}$O$_{3}$界面原子结构，明确衬底取向对界面质量的影响，为高性能功率电子异质结器件制备提供依据。
AI 中文摘要
NiO/Ga$_{2}$O$_{3}$异质结因Ga$_{2}$O$_{3}$具有超宽带隙和晶圆级可用性、NiO可实现可控p型掺杂，在功率电子领域受到广泛关注。然而，NiO/Ga$_{2}$O$_{3}$界面的结构仍未得到充分探索，这主要是由于二者分别为立方和单斜晶系，不同晶体结构形成的结较为复杂。本研究利用像差校正扫描透射电子显微镜（STEM），结合界面建模与图像模拟，针对Ga$_{2}$O$_{3}$衬底的(100)、(-201)和(001)取向，研究NiO/Ga$_{2}$O$_{3}$界面的原子结构。我们评估了界面的突变性与一致性，并将其与计算得到的界面模型进行对比，提出了精确的原子结构，同时评估了单斜晶系Ga$_{2}$O$_{3}$晶体结构的复杂性可能引发的潜在结构变化。我们的界面分析表明，应更加关注(100)取向的Ga$_{2}$O$_{3}$，将其作为制备高质量、低缺陷密度NiO/Ga$_{2}$O$_{3}$异质结器件的候选材料。重要的是，我们考虑了STEM成像过程中样品厚度及三维到二维投影的影响，以区分这类效应与真实晶体变化的差异。本研究揭示了衬底取向对NiO薄膜及界面质量的影响，为改善异质结性能提供了途径，同时强调了解读这些界面稳定性及层间相形成时需考虑的重要因素，这对将其集成到可靠、稳定的功率电子器件中至关重要。
英文摘要
NiO/Ga$_{2}$O$_{3}$ heterojunctions have garnered significant attention for use in power electronics due to the ultrawide bandgap and wafer-scale availability of Ga$_{2}$O$_{3}$ and the controllable p-type doping of NiO. However, the structure of NiO/Ga$_{2}$O$_{3}$ interfaces remains underexplored, largely due to the complexity of the junction between their dissimilar cubic and monoclinic crystal structures. Here we investigate the atomistic structure of the NiO/Ga$_{2}$O$_{3}$ interface for (100), (-201), and (001) oriented Ga$_{2}$O$_{3}$ substrates using aberration-corrected scanning transmission electron microscopy (STEM) in combination with interface modeling and image simulations. We evaluate the abruptness and consistency of the interfaces and compare them to calculated interface models, proposing precise atomic structures and assessing potential structural variation arising from complexity of the monoclinic Ga$_{2}$O$_{3}$ crystal structure. Our interface analysis supports increased focus on (100) oriented Ga$_{2}$O$_{3}$ as a candidate for fabricating high quality, low defect density NiO/Ga$_{2}$O$_{3}$ heterojunction devices. Importantly, we consider the effects of specimen thickness and 3D-to-2D projection during the STEM imaging process to differentiate such effects from real crystal variations. This work provides insight into the effect of substrate orientation on NiO film and interface quality, creating a pathway to improving heterojunction properties. It further highlights important considerations for interpretation of stability and interlayer phase formation in these interfaces, which is crucial for their integration into reliable and robust power electronic devices.
Comments16 pages, 14 figures, including Supplementary Material
