平面Si/PCBM与纳米Si/PCBM有机-无机杂化异质结的对比研究（英文）

Comparative Study on Planar-silicon and Nano-silicon Si/PCBM Inorganic-organic Hybrid Junctions

本研究采用平面硅与纳米硅分别与旋涂法生长的[6,6]-苯基C61-丁酸甲酯(PCBM)形成有机–无机杂化异质结,对比研究了两种异质结界面电学特性的差异。结果显示,平面Si/PCBM和纳米Si/PCBM两种异质结都表现出明显的整流特性,但相对于平面Si/PCBM异质结,纳米Si/PCBM异质结有较大的导通电压和较小的电流密度。为了深入研究导致这种差异的相关物理机制,通过阻抗谱(IS)表征技术进一步研究了两种异质结因界面变化而产生的电阻、电容的变化趋势。阻抗测试分析表明,Si/PCBM异质结界面存在的大量缺陷致使寄生效应进一步增大,影响了器件中电荷的输运。

Inorganic-organic heterojunction devices based on organic polymer and inorganic semiconductors has attracted extensive attention for high performance hybrid solar cell applications, due to the combined advantage of high carrier mobility of inorganic semiconductors and easy processing, strong absorption of organic polymers. In this study, both planar-Si and nano-Si were combined with spin-coated [6, 6]-phenyl C61-butyric acid methyl ester （PCBM） organic film to form Si/PCBM inorganic/organic hybrid junctions. A comparative study was per- formed through quantitative electrical analysis of planar-Si/PCBM and nano-Si/PCBM, respectively. In general, both devices exhibited a rectifying diode-like behavior. However, a higher turn-on voltage and smaller current density were observed from nano-Si/PCBM junctions, which was in contradiction with the expectation from the view of junction area. The corresponding mechanisms were further investigated with measurements of impedance spectroscopy （IS）. Our results indicated that this abnormal electrical characteristic of nano-Si/PCBM compared with normal p-n junction was highly associated with the parasitic effects caused by the defect states at the junc- tion interface.