Contact Doping for Vertical Organic Field-Effect Transistors
Contact Doping for Vertical Organic Field-Effect Transistors
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DOI：
10.1002/adfm.201504377
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发表时间：
2016-02-02
影响因子：
19
通讯作者：
Leo, Karl
中科院分区：
文献类型：
--
作者：
Guenther, Alrun A.;Sawatzki, Michael;Leo, Karl
掺杂是克服短沟道有机场效应晶体管 (OFET) 接触限制的有力工具，过去已成功用于改善 OFET 中的电荷载流子注入。本研究将这一熟悉的概念应用于垂直有机场效应晶体管（VOFET）的架构，由于沟道长度非常短，这些晶体管通常受到注入的严重限制。本研究表明，通过在 VOFET 源电极下方添加常见的 p 掺杂剂 C60F36 作为薄注入层，可以显着增强以并五苯为活性材料的 p 型 VOFET 的性能，从而使通态电流和开/关比增加一个数量级。本研究进一步研究了并五苯和 p 型掺杂剂的混合注入层，发现这种改进不如纯掺杂剂层明显，并且取决于注入层中掺杂剂分子的浓度。通过将转移长度方法应用于等效的 OFET 几何结构，本研究最终能够将观察到的改进与转移长度的减小联系起来，因此可以得出结论，该长度是一个关键参数，必须集中进一步的改进工作来实现真正的短沟道 VOFET。
Doping is a powerful tool to overcome contact limitations in short-channel organic field-effect transistors (OFETs) and has been successfully used in the past to improve the charge carrier injection in OFETs. The present study applies this familiar concept to the architecture of vertical organic field-effect transistors (VOFETs), which are often severely limited by injection due to their very short channel lengths. The present study shows that the performance of p-type VOFETs with pentacene as an active material can be significantly enhanced by the addition of the common p-dopant C60F36 as a thin injection layer underneath the VOFET source electrode, resulting in an increase of On-state current and On/Off ratio by one order of magnitude. The present study further investigates mixed injection layers of pentacene and the p-dopant and finds that the improvement is less pronounced than for the pure dopant layers and depends on the concentration of dopant molecules in the injection layer. Through application of the transfer length method to equivalent OFET geometries, the present study is finally able to link the observed improvement to a decrease in transfer length and can thus conclude that this length is a crucial parameter onto which further improvement efforts have to be concentrated to realize true short-channel VOFETs.