Charge transport through individual perylene-bisimide DNA aggregates using single-walled carbon nanotubes as contact leads

该项目的目标是开发新的技术来测量依赖于单壁碳纳米管（SWNTs）作为接触引线的单个基于DNA的分子聚集体的传输特性。我们将使用透射电子显微镜中的电子束将纳米间隙切割成SiN膜和沉积在其上的单壁碳纳米管。由此产生的单壁碳纳米管纳米接触对将与不同长度的自组装的基于二萘嵌苯双酰亚胺的DNA聚集体桥接。这样的聚集体允许研究通过明确定义长度的DNA链的电荷传输。二萘嵌苯-双酰亚胺分子作为（1）将DNA连接到CNT-引线上的锚基团和（2）通过DNA链作为电子跳跃的中间电荷岛。以这种方式，可以研究DNA纳米聚集体的电导。预计与天然DNA相比，由于存在作为人工可充电岛的二萘嵌苯双酰亚胺发色团，其之间通过跳跃过程发生电子传输，因此电导率得到改善。接触形成将在液体环境中原位监测，而测量将在不同的液体环境和真空中进行。后者还允许研究低温传输特性。由于所得到的单壁碳纳米管引线的小尺寸，分子的电荷状态可以通过附近的栅电极来控制。

The goal of this project is the development of novel technique to measure the transport properties of individual DNA-based molecular aggregates relying on single walled carbon nanotubes (SWNTs) as contact leads. We shall use the electron beam in a transmission electron microscope to cut nanogaps into a SiN-membrane and a SWNT deposited on it. The resulting pair of SWNT nano-contacts will be bridged with self-assembled perylene bisimide-based DNA-aggregates of different lengths. Such aggregates allow to study the charge transport through DNA-strands of well defined length. The perylene-bisimide molecules act as (1) anchor groups for the attachment of the DNA to the CNT-leads and (2) as intermediate charge islands for the hopping of electrons via the DNA strands. In this way, the conductance of DNA-nanoaggregates can be studied. It is expected that the conductivity is improved compared to the natural DNA due to the presence of the perylene bisimide chromophores as artificial chargable islands, between which electron transport occurs via hopping processes. The contact formation will be monitored in-situ in liquid environment, while the measurements will be performed both in different liquid environments and in vacuum. The latter also allows to study the low-temperature transport properties. Because of the small dimensions of the resulting SWNT leads, the charge state of the molecules can be controlled by means of nearby gate electrodes.