非晶/微晶相变域硅薄膜及其太阳能电池

Transition films from amporphous to microcrystalline silicon and solar cells

采用甚高频等离子体增强化学气相沉积(VHF_PECVD)法,成功制备出从非晶到微晶过渡区域的硅薄膜.样品的微结构、光电特性及光致变化的测量结果表明这些处于相变域的硅薄膜兼具非晶硅优良的光电性质和微晶硅的稳定性.用这种两相结构的材料作为本征层制备了p_i_n太阳能电池,并测量了其稳定性.结果在AM1.5(100mW cm2)的光强下曝光800—5000min后,开路电压略有升高,转换效率仅衰退了2.9%.

A series of hydrogenated silicon films near the threshold of crystallinity was prepared by very high frequency plasmaenhanced chemical vapor deposition (VHF-PECVD)from a mixture of SiH4 diluted in H-2. The effect of hydrogen dilution ratios R = [H-2]/[SiH4] on the microstructure of the films was investigated. The photoelectronic properties and stability of the films were studied as a function of crystalline fraction. The results show that the diphasic films gain both the fine photoelectric properties like a-Si: H and high stability like mu w-Si:H. By using the diphasic silicon films as the intrinsic layer, p-i-n junction solar cells were prepared. Current-voltage (J-V) characteristics and stability of the solar cells were measured under an AM1.5 solar simulator. We observed a light-induced increase of 5.2% in the open-circuit voltage (V-oc) and a light-induced degradation of similar to 2.9% inefficiency.