Hyperdoping germanium with gold is a potential method to produce room-temperature short-wavelength-infrared radiation (SWIR; $1.4–3.0\mu \mathrm{m}$) photodetection. We investigate the charge carrier dynamics, light absorption, and structural properties of gold-hyperdoped germanium ($\mathrm{Ge}$:$\mathrm{Au}$) fabricated with varying ion implantation and nanosecond pulsed laser melting conditions. Time-resolved terahertz spectroscopy (TRTS) measurements show that $\mathrm{Ge}$:$\mathrm{Au}$ carrier lifetime is significantly higher than that in previously studied hyperdoped silicon systems. Furthermore, we find that lattice composition, sub-band-gap optical absorption, and carrier dynamics depend greatly on hyperdoping conditions. We use density functional theory (DFT) to model dopant distribution, electronic band structure, and optical absorption. These simulations help explain experimentally observed differences in optical and optoelectronic behavior across different samples. DFT modeling reveals that substitutional dopant incorporation has the lowest formation energy and leads to deep energy levels. In contrast, interstitial or dopant-vacancy complex incorporation yields shallower energy levels that do not contribute to sub-band-gap light absorption and have a small effect on charge carrier lifetimes. These results suggest that it is promising to tailor dopant incorporation sites of $\mathrm{Ge}$:$\mathrm{Au}$ for SWIR photodetection applications.

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金掺杂锗的载流子动力学和吸收特性：洞察裁剪缺陷能量学

用金超掺杂锗是产生室温短波长红外辐射 (SWIR; $1.4——3.0\mu \mathrm{米}$) 光电检测。我们研究了金掺杂锗的电荷载流子动力学、光吸收和结构特性。$葛$：$金$) 使用不同的离子注入和纳秒脉冲激光熔化条件制造。时间分辨太赫兹光谱 (TRTS) 测量表明，$葛$：$金$载流子寿命明显高于先前研究的超掺杂硅系统。此外，我们发现晶格组成、子带隙光吸收和载流子动力学在很大程度上取决于超掺杂条件。我们使用密度泛函理论 (DFT) 来模拟掺杂分布、电子能带结构和光吸收。这些模拟有助于解释通过实验观察到的不同样品之间光学和光电行为的差异。DFT 模型表明，替代掺杂剂掺入具有最低的形成能并导致深能级。相比之下，填隙或掺杂剂空位复合物的结合产生更浅的能级，这些能级对子带隙光吸收没有贡献，并且对电荷载流子的寿命影响很小。$葛$：$金$ 用于 SWIR 光电检测应用。