Studying Transient Carrier Behaviors in Pentacene Field Effect Transistors Using Visualized Electric Field Migration
Studying Transient Carrier Behaviors in Pentacene Field Effect Transistors Using Visualized Electric Field Migration
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DOI：
10.1021/jp900779d
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发表时间：
2009-06-11
影响因子：
3.7
通讯作者：
Iwamoto, Mitsumasa
中科院分区：
文献类型：
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作者：
Manaka, Takaaki;Liu, Fei;Iwamoto, Mitsumasa
时间分辨显微光学二次谐波发生（TRM-SHG）成像基于电场分布的迁移研究了具有金和银电极的并五苯场效应晶体管（FET）的瞬态载流子行为。我们发现使用Ag和Au电极的器件之间并五苯FET沟道中电场分布的时间演化有很大不同：代表载流子积累不足的增强SHG信号在Au源电极边缘迅速衰减，而信号衰减但仍保留在Ag电极边缘。有趣的是，在两种情况下，描述通道区域中载体片边缘的 SHG 信号峰值都以时间平方根的方式迁移。提出了一个简单的模型来统一解释实验观察结果，并使用二维耦合扩散漂移对瞬态载流子行为和电场迁移进行了数值模拟，泊松方程很好地支持了该模型。特别是，结果表明，基于该模型评估的 FET 沟道中的载流子迁移率与金属电极无关，这表明使用 Au 和 Ag 电极的器件之间的体载流子传输相同。
Time-resolved microscopic optical second harmonic generation (TRM-SHG) imaging was used to study the transient carrier behaviors in pentacene field effect transistor (FET) with Au and Ag electrodes on the basis of the migration of the electric field profile. We found that the time evolution of the electric field distribution in the pentacene FET channel was quite different between the devices using Ag and Au electrodes: enhanced SHG signal representing insufficient carrier accumulation decayed rapidly at the edge of the Au source electrode, while the signal decayed but remained at the edge of the Ag electrode. Interestingly, the peaks of the SHG signal depicting the edge of the carrier sheet in the channel region in both cases migrated in a way of the square root of time. A simple model was proposed to uniformly account for the experimental observations, and a numerical simulation on the transient carrier behaviors with the electric field migration using two-dimensional coupled diffusion-drift and the Poisson equations well-supported this model. Particularly, the results showed that the evaluated carrier mobility in the FET channel based on this model was independent of the metal electrode, indicating identical carrier transport in the bulk between the devices using Au and Ag electrodes.