Hole mobility in thermally evaporated pentacene: Morphological and directional dependence
Hole mobility in thermally evaporated pentacene: Morphological and directional dependence
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DOI：
10.1063/1.4922422
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发表时间：
2015-06-08
影响因子：
4
通讯作者：
Leo, Karl
中科院分区：
文献类型：
--
作者：
Guenther, Alrun A.;Widmer, Johannes;Leo, Karl
并五苯作为有机场效应晶体管的活性材料已被广泛研究，因为它沿其优选的传输方向显示出非常好的电荷载流子迁移率沿着。在这篇文章中，我们通过在传统的横向有机场效应晶体管（OFFET）中测量并五苯薄膜中的空穴输运来研究并五苯薄膜中的空穴输运，这产生了沿并五苯的a-b平面沿着的空穴迁移率，并且通过最近发表的电势映射（POEM）方法，这允许直接提取垂直于衬底的电荷载流子迁移率，在这种情况下垂直于a-b平面，而无需假设特定的传输模型。虽然沿a-b平面的迁移率沿着-由OFET测量确定-被发现在0.45 cm（2）/Vs的范围内，垂直于该平面的传输显示出至少低一个数量级的平均迁移率。调查也如何这些有效的迁移率值取决于并五苯膜的沉积速率，我们发现，晶粒尺寸的减少，增加沉积速率的原因，流动性降低平行和垂直于基板由于晶界的数量增加，以克服。对于面外输运，发现这种效应在高于2.5埃/秒的沉积速率下饱和。VC 2015作者。所有文章内容，除非另有说明，是根据知识共享署名3.0未移植许可证许可。
Pentacene has been extensively studied as an active material for organic field-effect transistors as it shows very good charge carrier mobility along its preferred transport direction. In this contribution, we investigate the hole transport in pentacene thin films by measurement in conventional lateral organic field-effect transistors (OFETs), which yields the hole mobility along the a-b plane of pentacene, and by the recently published potential mapping (POEM) approach, which allows for direct extraction of the charge carrier mobility perpendicular to the substrate, in this case perpendicular to the a-b plane, without the assumption of a specific transport model. While the mobility along the a-b plane-determined from OFET measurements-is found to be in the region of 0.45 cm(2)/Vs, transport perpendicular to this plane shows an average mobility at least one order of magnitude lower. Investigating also how these effective mobility values depend on the deposition rate of the pentacene films, we find that the decrease in grain size for increasing deposition rate causes the mobility to decrease both parallel and perpendicular to the substrate due to the increased number of grain boundaries to be overcome. For the out-of-plane transport, this effect is found to saturate for deposition rates higher than 2.5 angstrom/s. VC 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.