It has been established that hydrogen (H) plays a key role in p-type doping of GaN and it must be removed by dissociation of the Mg–H complex in order to achieve p-type conductivity. However, in carbon (C)-doped semi-insulating GaN, which is the core component of power electronic devices, the role of H, especially the formation and dissociation process of C–H defects, has remained to date a mystery. In this work, we provide a direct evidence for the interaction between H and C in the form of the C N − H i complex in as-grown C-doped GaN. The complex can be dissociated into C N − and H + after post-growth annealing. The activation energy is estimated to be about 2.3–2.5 eV from the temperature-dependent annealing experiments. Our study reveals that the C N − H i complex plays an essential role in understanding the variation of optical and electronic properties of C-doped GaN.

中文翻译：

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氢与碳相互作用的直接证据：半绝缘 GaN 中的 C-H 复合物

已经确定氢 (H) 在 GaN 的 p 型掺杂中起关键作用，必须通过解离 Mg-H 复合物将其去除，以实现 p 型导电性。然而，在作为电力电子器件核心部件的碳 (C) 掺杂半绝缘 GaN 中，H 的作用，尤其是 C-H 缺陷的形成和解离过程，至今仍是个谜。在这项工作中，我们为在生长的 C 掺杂 GaN 中以 CN - H i 复合物形式的 H 和 C 之间的相互作用提供了直接证据。在生长后退火后，复合物可以分解为 CN - 和 H + 。根据温度依赖性退火实验，活化能估计约为 2.3-2.5 eV。