SBIR Phase II: Fabrication of Low-bandgap Nano-crystalline SiGeC Thin Films Using the Plasma Enhanced Chemical Vapor Deposition (PECVD) Technique

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。SBIR第二阶段项目是开发薄膜叠层太阳能电池，由纳米晶硅和硅碳（nc-Si和nc-Si：C）吸收材料组成，转换效率约为20%。第一阶段项目成功开发了关键组件之一，即本征nc-Si：C，其带隙Eg为~ 1.5 eV，具有良好的光电性能。这种关键材料最初将用于第二阶段，以单结配置制造电池，效率目标为~ 10%。以前，开发的“器件质量”nc-Si材料，Eg ~1.1eV，用于生产效率约8%的太阳能电池。将这两个器件集成在串联结配置中，预计效率可达18%。通过在p/i或i/n界面处使用缓冲层以及通过增加将提高开路电压Voc的晶粒尺寸，可以实现串联结器件效率的进一步提高，达到~ 20%。更高效率的薄膜串联太阳能电池对于实现广泛采用光伏能量产生系统所需的低成本是至关重要的。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This SBIR Phase II project is to develop thin film tandem solar cells, comprising of nanocrystalline silicon and silicon carbon (nc-Si and nc-Si:C) absorber materials, with a conversion efficiency of ~20%. The phase I project successfully developed one of the key components, i.e. intrinsic nc-Si:C with a band gap, Eg, of ~ 1.5 eV and with good opto-electronic properties. This key material will be used initially in phase II to fabricate cells in a single junction configuration with an efficiency goal of ~10%. Previously, developed "device quality" nc-Si materials, with Eg ~1.1eV, were used to produce solar cells with efficiency ~8%. Integrating the two devices in a tandem junction configuration is forecast to yield efficiencies of ~18%. Further improvement in the tandem junction device efficiency,to ~20%, may be achieved via the use of buffer layers at the p/i or i/n interfaces and by increasing the grain size which would boost the open circuit voltage, Voc.Higher efficiency thin film tandem solar cells will be critical to achieving the low costs necessary to achieve widespread adoption of photovoltaic energy generating systems.