Abstract Understanding and rationally controlling the interfacial electronic states of the Al2O3/diamond (Al2O3(001)/C(001)) appears to be crucial in the next generation oxide-semiconductor devices on the basis of diamond. In this work, the density functional theory computations are used to systematically elucidate the effects of the different terminated planar of Al2O3 and diamond on the electronic properties of the Al2O3/diamond interfaces. Results show that a two-dimensional hole gas can be created at the Al2O3(001)/C(001) heterointerface. In particular, for the most stable C Al interface under Al-rich condition, a strong p-type doping with obvious localization characteristics from charge transfer is achieved, which reveals a 2DHG generated at the C Al interface. Bader analysis reveals that the 0.047 e/unit-cell are transferred from the side of diamond into the side of Al2O3. In addition, the band alignments of Al2O3(001)/C(001) hetero–interface show a type-II staggered band configuration, and a VBO of 3.5 eV is independent of strain for the most stable C Al interface. The observation of the 2DHG at the C Al interface and the positive valence band offset will provide a practical guidance for further investigation for future diamond-based power devices.

中文翻译：

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Al2O3/金刚石界面工程在金刚石表面形成二维空穴气体

摘要 理解和合理控制 Al2O3/金刚石 (Al2O3(001)/C(001)) 的界面电子态对于基于金刚石的下一代氧化物半导体器件至关重要。在这项工作中，密度泛函理论计算用于系统地阐明 Al2O3 和金刚石的不同终止平面对 Al2O3/金刚石界面电子特性的影响。结果表明，可以在 Al2O3(001)/C(001) 异质界面处产生二维空穴气体。特别是，对于富铝条件下最稳定的 C Al 界面，实现了具有明显电荷转移局部化特征的强 p 型掺杂，这揭示了在 C Al 界面处生成的 2DHG。Bader 分析表明 0. 047 e/晶胞从金刚石一侧转移到 Al2O3 一侧。此外，Al2O3(001)/C(001) 异质界面的能带排列显示出 II 型交错能带结构，对于最稳定的 C-Al 界面，3.5 eV 的 VBO 与应变无关。对 C Al 界面处的 2DHG 和正价带偏移的观察将为未来基于金刚石的功率器件的进一步研究提供实用指导。