EFFICIENCY IMPROVEMENT OF POLYCRYSTALLINE SILICON SOLAR CELLS

太阳能电池用硅薄膜的制备实验研究了熔体急冷法制备硅薄膜的工艺条件，着重研究了薄膜尺寸与制备参数的关系。这些参数是喷射压力、大气压力、盘旋转速度、制备速度、盘材料和大气气体。流体动力学分析很好地解释了这些实验结果。晶界电子态密度;电子电导率和霍尔迁移率的温度依赖性的测量未掺杂和有意硼和磷掺杂的样品。双肖特基势垒模型在晶界处形成双耗尽层，作为光生载流子的阱，降低了收集效率。直流偏压下的场依赖电导定性地解释为载流子通过电子发射穿过晶界势垒的输运。本文提出了一种利用正介电各向异性液晶的场效应分析多晶硅电活性晶界的新方法，实验上承认。

Preparation of silcon films for solar cells; Preparation conditions of silicon thin films by the method of melt quenching were experimentally clarified especially on the relation of film dimentions and preparation parameters. These parameters were ejection pressure, atmospheric pressure, disc rotation speed, preparation speed, disc materials and atmospheric gases. Hydrodynamic analysis well interpreted these experimental results quntitatively.Electronic density of states at grain boundaries; The electronic conductivities and temperature dependence of Hall mobilities were measured on the undoped and intentionally boron and phosphorus doped samples. Double schottky barrier model which made double depletion layers at grain boundaties and works as sink for the photogenerated carries and reduce the collection efficiency. Field dependent conductivites under DC bias voltage were well interpreted qualitatively as the carrier transport through the thermionic emission across over the grain boundaries potential barriers.Grain boundaries electric field observation technique; A new method to analize electrically active grain boundaries of polycrystalline silicon by using a field effect of nematic liquid crystal with positive dielectric anisotropy is developed.Plasma passivation of grain boundaries were experimentally recognized.