Performance improvement mechanisms of organic thin-film transistors using MoOx-doped pentacene as channel layer
Performance improvement mechanisms of organic thin-film transistors using MoOx-doped pentacene as channel layer
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DOI：
10.1016/j.orgel.2011.07.016
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发表时间：
2011-11-01
影响因子：
3.2
通讯作者：
Chen, Hung-Chun
中科院分区：
文献类型：
--
作者：
Lee, Ching-Ting;Chen, Hung-Chun
制备并研究了具有不同MoOx掺杂的并五苯沟道层的有机薄膜晶体管（OTFT）。与没有MoOx掺杂剂的常规OTFT相比，具有0.50摩尔% MoOx掺杂的并五苯的OTFT的最大输出电流从-11.6 μ A增加到-37.9 μ A，有效场效应迁移率从0.71提高到1.60 cm（2）/V-s，阈值电压从-21.2降低到-14.8 V，并且开/关电流比从3.6 × 10（6）略微降低到1.2 × 10（6）。这是由于随着MoOx掺杂量的增加，MoOx掺杂并五苯的最高占据分子轨道（HOMO）逐渐接近Au功函数，从而降低了OTFT的接触电阻，并通过增加空穴密度和提高空穴注入效率来增强OTFT的p型特性。当MoOx的掺杂摩尔百分比大于0.50%时，输出电流和场效应迁移率随MoOx掺杂百分比的增加而降低。这是由于费米能级钉扎效应、空穴浓度的逐渐增加和结晶度的显著降低。(C)2011 Elsevier B. V.保留所有权利。
Organic thin-film transistors (OTFTs) with various MoOx-doped pentacene channel layers were fabricated and investigated. Compared the OTFTs with the 0.50 mol% MoOx-doped pentacene to the conventional OTFTs without MoOx dopant, the maximum output current was increased from -11.6 to -37.9 mu A, the effective field-effect mobility was enhanced from 0.71 to 1.60 cm(2)/V-s, the threshold voltage was reduced from -21.2 to -14.8 V, and the on/off current ratio slightly decreased from 3.6 x 10(6) to 1.2 x 10(6). The performance improvement was attributed to the highest occupied molecular orbital (HOMO) of the MoOx-doped pentacene gradually approached to the Au work function with increasing the doping percentage of MoOx, which led to reduce the contact resistance and to enhance the p-type characteristics of the MoOx-doped OTFTs by increasing the hole density and enhancing the hole-injection efficiency. However, the output current and the field-effect mobility decreased with an increase of the MoOx doping percentage, if the doping mole percentage of MoOx was higher than 0.50%. This behavior was attributed to the Fermi level pinning effect, gradual increase of hole concentration and significant degradation of crystallinity. (C) 2011 Elsevier B.V. All rights reserved.