掺硼纳米非晶硅的太阳能电池窗口层应用研究

Growth and Characterization of Boron-Doped na-Si:H Films Used as Window Layer Material of Solar Cells

本文通过等离子体增强化学气相沉积(PECVD)法沉积p型纳米非晶硅薄膜(na-Si∶H),系统地研究了掺杂气体比(B2H6/SiH4)、沉积温度、射频电源功率对薄膜结构、光学、电学性能的影响。研究表明,轻掺硼有利于非晶硅薄膜晶化,但随着掺硼量的增加,硼的"毒化"作用又使薄膜变为非晶态;与p型a-Si∶H相比,掺硼纳米硅薄膜的光学带隙Eopt较高,电导率较高,电导激活能较低,是一种很有潜力的太阳能电池窗口层材料。

The boron-doped, nano-amorphous silicon （na-Si：H） films were deposited by plasma enhanced chemical vapor deposition （PECVD） to fabricate the window layers of solar cells. The microstmctures and optical properties of the na-Si： H films were characterized by X-ray diffraction （XRD）, Raman spectrometre and UV-VI spectophotometer. The influence of film growth conditions, including the gas flow ratios of B2H6/SiH4, RF power, the flow rate of the doping gas, and the substrate temperature, on the and properties of the film was studied. The results show that the boron content significantly affects the grain size and crystalline volume fraction of the na-Si ： H films. For example, light boron doping favors crystallization of the na-Si： H. As boron dopant contents increases, the catalyst poisoning of boron results in amorphous phase. The B-doped na-Si： H has a larger optical band gap（ Eopt = 1.99eV）,higher conductivity and lower activation energy of conductivity than the p-type a-Si： H films. We suggest that the B-doped na-Si： H be a good window layer material of thin film solar-cells.