Rother Marcel, Schießl Stefan P, Zakharko Yuriy, Gannott Florentina, Zaumseil Jana
Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg , D-91058 Erlangen, Germany.
Institute for Physical Chemistry, Universität Heidelberg , D-69120 Heidelberg, Germany.
ACS Appl Mater Interfaces. 2016 Mar 2;8(8):5571-9. doi: 10.1021/acsami.6b00074. Epub 2016 Feb 19.
The ability to select and enrich semiconducting single-walled carbon nanotubes (SWNT) with high purity has led to a fast rise of solution-processed nanotube network field-effect transistors (FETs) with high carrier mobilities and on/off current ratios. However, it remains an open question whether it is best to use a network of only one nanotube species (monochiral) or whether a mix of purely semiconducting nanotubes but with different bandgaps is sufficient for high performance FETs. For a range of different polymer-sorted semiconducting SWNT networks, we demonstrate that a very small amount of narrow bandgap nanotubes within a dense network of large bandgap nanotubes can dominate the transport and thus severely limit on-currents and effective carrier mobility. Using gate-voltage-dependent electroluminescence, we spatially and spectrally reveal preferential charge transport that does not depend on nominal network density but on the energy level distribution within the network and carrier density. On the basis of these results, we outline rational guidelines for the use of mixed SWNT networks to obtain high performance FETs while reducing the cost for purification.
能够以高纯度选择和富集半导体单壁碳纳米管（SWNT），使得具有高载流子迁移率和开/关电流比的溶液处理纳米管网络场效应晶体管（FET）迅速兴起。然而，使用仅一种纳米管种类的网络（单手性）是否最佳，或者具有不同带隙的纯半导体纳米管的混合对于高性能FET是否足够，这仍然是一个悬而未决的问题。对于一系列不同的聚合物分类半导体SWNT网络，我们证明，在大带隙纳米管的致密网络中，极少量的窄带隙纳米管可以主导传输，从而严重限制导通电流和有效载流子迁移率。利用与栅极电压相关的电致发光，我们在空间和光谱上揭示了优先电荷传输，其不依赖于标称网络密度，而是依赖于网络内的能级分布和载流子密度。基于这些结果，我们概述了使用混合SWNT网络以获得高性能FET同时降低纯化成本的合理指导方针。
