基于氮化硅基质的硅量子点的低温生长及其性能研究

Efficient and cost effective is the goal of PV development. Silicon (Si) quantum dots are expected to be applied in the third generation of highly efficient solar cells due to a feature of adjustable band gap. To study its growth mechanism at low-temperature in order to achieve compatible process with existing silicon thin-film solar cell technology is of very important significance. This project intends to establish a low-temperature technology for silicon quantum dots embedded in silicon nitride matrix by using a PECVD technique combined with rapid photo-thermal annealing technique. Theoretically, a combination of thermodynamic and kinetic analysis can be used to study the low-temperature growth mechanism of Si quantum dots and the doping mechanism based on the mechanism of nucleation, thermal annealing and doping formation energy calculations. Experiments on the growth and doping of Si quantum dots at low temperature, PECVD growth combined with rapid photo-thermal annealing technology will be carried out to identify the key factors that affect the low-temperature growth of Si quantum dots and the efficiency of low-temperature doping. Ultimately, a relationship between the microstructure and optoelectronic properties of silicon quantum dots will be established. A solar cell will be designed and produced to verify the performances of silicon quantum dots. The study of this project will reveal the PECVD technology-based growth and doping mechanism of Si quantum dots at low temperature, and lay a foundation for a new generation of highly efficient solar cells.

高效、低成本是太阳电池的发展目标。硅（Si）量子点材料由于具有带隙可调等特点，有望在第三代高效太阳电池中获得应用，因此，研究其低温生长机制以实现与现有的硅薄膜电池工艺相兼容具有十分重要的意义。本项目拟采用PECVD技术结合快速光热退火技术实现氮化硅基质中硅量子点的低温生长。理论上，根据成核生长理论和光热退火机制，结合热力学和动力学过程的分析以及掺杂形成能的计算，研究Si量子点的低温生长机制和掺杂机制。实验上，开展Si量子点低温生长和掺杂研究，采用PECVD生长方法结合快速光热退火技术，找出影响Si量子点低温生长的关键因素和实现低温掺杂的途径，最终获得硅量子点的低温生长技术；同时，开展掺杂Si量子点的结构和光电性能研究，建立微结构与光电性能间的对应关系；通过电池设计与制作，验证硅量子点性能。本项目的研究将揭示以PECVD技术为基础的Si量子点低温生长和掺杂机制，为新一代高效太阳电池奠定基础。

硅量子点材料由于具有带隙可调等特点，可用于新一代太阳电池。研究其低温生长机制以实现与现有的硅薄膜电池工艺相兼容具有十分重要的意义。本课题对硅量子点的制备工艺、退火工艺和生长机制等进行了深入研究，通过快速光热退火的工艺改进和引入微波退火等手段，找到了降低硅量子点生长温度的有效手段（滤光光热退火和微波退火均能使硅量子点的生长温度较传统的快速光热退火降低200℃）；在尺寸可控的硅量子点多层结构的制备、微结构表征、光电特性和输运性质等方面进行了较深入和系统的研究；我们初步设计和制备了pn型硅量子点太阳电池，获得了原理性器件，对器件性能进行了测试和研究，最高光电转换效率为7.05%。项目实施期间，共发表论文14篇（SCI收录10篇），4件授权国家发明专利，并与国际上许多研究组进行了合作交流，圆满完成了预定的研究目标，为下一步的工作打下了良好的基础。