Screw dislocations are generally considered to be one of the main causes of GaN-based device leakage, but so far, nearly no reports have focused on the effects of open-core screw dislocations on device leakage currents experimentally. In this paper, we use a conductive atomic force microscope to characterize the electronic properties of threading dislocations (TDs) in the GaN layer. The full-core screw dislocations and mixed dislocations are found to provide conductive paths for device leakage currents. In terms of the contribution to device leakage currents, the edge and open-core screw dislocations have smaller effects than the full-core screw dislocations and mixed dislocations. We use isotropic linear elasticity theory and density functional theory calculations to model the core atomic structures of TDs and calculate the corresponding electronic structures. The results show that screw dislocations with full-core structures are found to introduce both deep and shallow energy states within the energy gap dispersedly, while the open-core screw dislocations and the most edge dislocations introduce only shallow energy states. The calculated electronic structures of each type of dislocation are systematically compared and correlated with experimental observations. Our findings demonstrate that full-core screw dislocations and mixed dislocations in the GaN layer have a far more detrimental impact on device leakage than edge and open-core screw dislocations.

中文翻译：

---

是否所有螺旋位错都会导致基于 GaN 的器件发生泄漏？

螺旋位错通常被认为是 GaN 基器件泄漏的主要原因之一，但到目前为止，几乎没有报道集中在实验上关注开芯螺旋位错对器件泄漏电流的影响。在本文中，我们使用导电原子力显微镜来表征 GaN 层中穿透位错 (TD) 的电子特性。发现全核螺旋位错和混合位错为器件漏电流提供导电路径。在对器件漏电流的贡献方面，刃型和开芯螺型位错的影响小于全芯型螺型位错和混合型位错。我们使用各向同性线性弹性理论和密度泛函理论计算来模拟 TDs 的核心原子结构并计算相应的电子结构。结果表明，具有全核结构的螺旋位错在能隙内分散地引入深能态和浅能态，而开核螺旋位错和大多数刃位错仅引入浅能态。计算出的每种位错的电子结构与实验观察进行系统比较和关联。我们的研究结果表明，与边缘和开核螺旋位错相比，GaN 层中的全核螺旋位错和混合位错对器件泄漏的不利影响要大得多。结果表明，具有全核结构的螺旋位错在能隙内分散地引入深能态和浅能态，而开核螺旋位错和大多数刃位错仅引入浅能态。计算出的每种位错的电子结构与实验观察进行系统比较和关联。我们的研究结果表明，与边缘和开核螺旋位错相比，GaN 层中的全核螺旋位错和混合位错对器件泄漏的不利影响要大得多。结果表明，具有全核结构的螺旋位错在能隙内分散地引入深能态和浅能态，而开核螺旋位错和大多数刃位错仅引入浅能态。计算出的每种位错的电子结构与实验观察进行系统比较和关联。我们的研究结果表明，与边缘和开核螺旋位错相比，GaN 层中的全核螺旋位错和混合位错对器件泄漏的不利影响要大得多。计算出的每种位错的电子结构与实验观察进行系统比较和关联。我们的研究结果表明，与边缘和开核螺旋位错相比，GaN 层中的全核螺旋位错和混合位错对器件泄漏的不利影响要大得多。计算出的每种位错的电子结构与实验观察进行系统比较和关联。我们的研究结果表明，与边缘和开核螺旋位错相比，GaN 层中的全核螺旋位错和混合位错对器件泄漏的不利影响要大得多。