2D electronic systems for device applications

In the author´s presentation, the author will focus on devices from MoS₂. The author will discuss why di-chalgogenides are not “yet another” new material class, but instead offer true advantages towards electronic applications. In particular the author´s work will elucidate the impact of contacts in case of MoS₂ field-effect transistors. Through a thorough study of the impact of various contact source/drain metal electrodes and layer thickness on the “effective” mobility of MoS₂ devices, they were able to gather critical insights into the electronic properties of this di-chalcogenide. This study supports in particular the notion that an apparently linear device I_d-V_ds characteristic is by no means evidence of an Ohmic contact and that contacts frequently mask the true mobility specs of novel low-dimensional materials. Moreover, the study on the impact of the layer thickness reveals important information about the usefulness of multi-layered structures for improved device performance and helps to understand how interlayer resistances and screening between individual MoS₂ layers determine the overall device performance. Evaluating the resistor network that is used to describe the properties of multi-layer MoS₂ and comparing the individual resistor components with those in other materials such as graphene allows us to gain a detailed understanding about the distribution of the electrical current in 2D layered materials. This understanding is believed to be a key aspect to determine the layout and design of future generations of devices from low-dimensional structures.