Yi H T, Gartstein Y N, Podzorov V
Dept. of Physics, Rutgers University, Piscataway, NJ 08854, USA.
Dept. of Physics, University of Texas at Dallas, Richardson, TX, USA.
Sci Rep. 2016 Mar 30;6:23650. doi: 10.1038/srep23650.
Hall effect measurements are important for elucidating the fundamental charge transport mechanisms and intrinsic mobility in organic semiconductors. However, Hall effect studies frequently reveal an unconventional behavior that cannot be readily explained with the simple band-semiconductor Hall effect model. Here, we develop an analytical model of Hall effect in organic field-effect transistors in a regime of coexisting band and hopping carriers. The model, which is supported by the experiments, is based on a partial Hall voltage compensation effect, occurring because hopping carriers respond to the transverse Hall electric field and drift in the direction opposite to the Lorentz force acting on band carriers. We show that this can lead in particular to an underdeveloped Hall effect observed in organic semiconductors with substantial off-diagonal thermal disorder. Our model captures the main features of Hall effect in a variety of organic semiconductors and provides an analytical description of Hall mobility, carrier density and carrier coherence factor.
霍尔效应测量对于阐明有机半导体中的基本电荷传输机制和本征迁移率非常重要。然而，霍尔效应研究经常揭示出一种非常规行为，这种行为无法用简单的带半导体霍尔效应模型轻易解释。在这里，我们开发了一种在带载流子和跳跃载流子共存状态下有机场效应晶体管中的霍尔效应分析模型。该模型得到了实验的支持，它基于一种部分霍尔电压补偿效应，这种效应的出现是因为跳跃载流子对横向霍尔电场做出响应，并在与作用于带载流子的洛伦兹力相反的方向上漂移。我们表明，这尤其会导致在具有大量非对角热无序的有机半导体中观察到不发达的霍尔效应。我们的模型捕捉了各种有机半导体中霍尔效应的主要特征，并提供了霍尔迁移率、载流子密度和载流子相干因子的分析描述。
