Abstract Thin films comprising three dimensional germanium (Ge) quantum dot lattices formed by nitrogen (N) assisted magnetron sputtering deposition in alumina (Al2O3) matrix have been studied for light harvesting purposes. In order to expand the application of this material it is necessary to reduce germanium oxidation and to achieve stabilization of the germanium/alumina interface. Effects of tuning the N concentration, substrate temperature and Ge sputtering power during the films preparation are monitored. It is shown that the N presence not only reduces Ge oxidation during annealing but also affects the internal structure, size and arrangement of Ge quantum dots. Additionally, the deposition temperature and Ge sputtering power are used to tune the Ge quantum dot size, separation and the regularity of their positions. It is shown that the optical and electrical properties of the films, especially their photo-induced current, and quantum efficiency are strongly tunable by the deposition conditions. Moreover, a significant photo-response and effect of multiple exciton generation effect is observed. The materials presented could be used as a sensitive layer for photodetectors or photovoltaic light harvesting devices. The presented tools can be used for future fine tuning of the material to achieve the optimal quantum efficiency.

中文翻译：

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氮辅助沉积法制备氧化铝中的锗量子点晶格：结构和光电转换效率

摘要 出于光收集目的，研究了由氮 (N) 辅助磁控溅射沉积在氧化铝 (Al2O3) 基质中形成的三维锗 (Ge) 量子点晶格薄膜。为了扩大这种材料的应用，必须减少锗的氧化并实现锗/氧化铝界面的稳定化。监测在薄膜制备过程中调整 N 浓度、衬底温度和 Ge 溅射功率的影响。结果表明，N 的存在不仅减少了退火过程中的 Ge 氧化，而且还会影响 Ge 量子点的内部结构、尺寸和排列。此外，沉积温度和 Ge 溅射功率用于调整 Ge 量子点的尺寸、间隔和位置的规律性。结果表明，薄膜的光学和电学特性，尤其是它们的光生电流和量子效率，可以通过沉积条件进行强烈调节。此外，观察到显着的光响应和多重激子生成效应。所提供的材料可用作光电探测器或光伏光收集装置的敏感层。所提出的工具可用于未来对材料的微调，以实现最佳的量子效率。所提供的材料可用作光电探测器或光伏光收集装置的敏感层。所提出的工具可用于未来对材料的微调，以实现最佳的量子效率。所提供的材料可用作光电探测器或光伏光收集装置的敏感层。所提出的工具可用于未来对材料的微调，以实现最佳的量子效率。