Gallium nitride is an increasingly technologically relevant material system. While donor doping GaN to low and intermediate dopant concentrations using silicon and germanium has become routine, compensation mechanisms activate under very high donor doping, limiting the maximum electron concentration achievable with either dopant in the degenerate doping regime. This effect, and how it differs between the two dopants, is investigated by hybrid functional density functional theory calculations and grand canonical thermodynamics models and is found to be due to the onset of multi-member Ga vacancy-donor substitutional complexes under degenerate doping conditions. The differing energetics of Ge- and Si-related complexes leads to different responses, ultimately making Ge the more effective donor in degenerate conditions.

中文翻译：

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简并施主掺杂 GaN 中的配合物和补偿

氮化镓是一种与技术越来越相关的材料系统。虽然使用硅和锗将 GaN 掺杂到低和中等掺杂剂浓度已成为常规，但补偿机制在非常高的施主掺杂下激活，限制了在简并掺杂状态下使用任一掺杂剂可实现的最大电子浓度。通过混合功能密度泛函理论计算和正则热力学模型研究了这种效应以及两种掺杂剂之间的差异，发现是由于在简并掺杂条件下多成员 Ga 空位-供体置换复合物的出现。Ge 和 Si 相关配合物的不同能量导致不同的响应，最终使 Ge 成为简并条件下更有效的供体。