EPFL STI IMX LOMM, PH D2 435, Station 31015 Lausanne, Switzerland.
Langmuir. 2010 Sep 21;26(18):15044-9. doi: 10.1021/la102060u.
In organic thin-film transistors (OTFTs), the conducting channel is located near the interface between the organic semiconductor and the oxide dielectric; this interface is crucial for transistor performance. Self-assembled monolayers (SAMs) on the interface reduce the negative influences of the oxide dielectric surface by decreasing the coupling of the carriers at the gate and the role of the active surface defects on transfer. In this paper, we show that SAMs carrying a dipole moment determine the OTFT performance by controlling the charge transfer between the oxide dielectric and the semiconductor. The charges introduced into the semiconductor by this transfer (i.e., residual carriers) lead to a threshold shift to positive values, as well as a decrease in the contact resistance and an increase in the apparent mobility. In this study, other effects of the SAMs, such as the gate potential shift in the channel or a direct reaction between semiconductor and SAM molecules, can be excluded as dominant processes.
在有机薄膜晶体管（OTFT）中，导电沟道位于有机半导体和氧化物电介质的界面附近；这个界面对于晶体管的性能至关重要。界面上的自组装单分子层（SAM）通过减少栅极和活性表面缺陷在传输过程中的载流子耦合，降低了氧化物电介质表面的负面影响。在本文中，我们表明，通过控制氧化物电介质和半导体之间的电荷转移，带有偶极矩的 SAM 决定了 OTFT 的性能。通过这种转移引入到半导体中的电荷（即剩余载流子）导致阈值向正值偏移，以及接触电阻减小和表观迁移率增加。在本研究中，可以排除 SAM 的其他影响，例如通道中的栅极电位偏移或半导体和 SAM 分子之间的直接反应，作为主要过程。
