On the Use of Photocurrent Imaging To Determine Carrier Diffusion Lengths in Nanostructured Thin-Film Field-Effect Transistors
On the Use of Photocurrent Imaging To Determine Carrier Diffusion Lengths in Nanostructured Thin-Film Field-Effect Transistors
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DOI：
10.1021/acs.jpcc.8b06734
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发表时间：
2018-07
期刊：
影响因子：
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通讯作者：
Ruijuan Xiao;Yasen Hou;M. Law;Dong Yu
中科院分区：
文献类型：
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作者：
Ruijuan Xiao;Yasen Hou;M. Law;Dong Yu
扫描光电流显微镜（SPCM）已被广泛用于研究纳米结构场效应晶体管（FET）中的电荷输运和复合。横向电场调制的光电流映射提供了对局部电子能带弯曲和载流子输运的重要见解。然而，实验结果的分析往往是基于不合理的假设。特别是，不均匀的载流子浓度引起的栅极偏置和局部光激发可能会显着影响的光电流分布，但这些影响没有被考虑在以前的工作。此外，载流子寿命是载流子浓度的函数，并且在门控沟道中可能具有大的空间变化，这可能导致进一步的复杂化。在这里，我们对局部光激发下的薄膜FET进行了严格的二维横截面建模。我们的模拟结果验证了精确的少数载流子扩散长度可以。
Scanning photocurrent microscopy (SPCM) has been widely used as a powerful experimental technique to investigate charge transport and recombination in nanostructured field-effect transistors (FETs). Photocurrent mapping modulated by transverse electric field provides critical insights into local electronic band bending and carrier transport. However, the analysis of experimental results is often based on unjustified assumptions. In particular, the inhomogeneous carrier concentration induced by gate bias and local photoexcitation may significantly influence the photocurrent distribution, but these effects have not been considered in previous work. Furthermore, carrier lifetime is a function of carrier concentration and can have a large spatial variation in a gated channel, which may lead to further complication. Here, we perform rigorous two-dimensional cross-sectional modeling of thin-film FETs under local photoexcitation. Our simulation results validate that accurate minority carrier diffusion lengths ca...