The undertaken work under objective 1 led to the discovery of ultra-low energy barriers in metal-semiconductor interfaces (N.J. Townsend et al., 2D Mater. 5, 025023, 2018). Additionally, methods for the formation and measurements of low barriers in 2D semiconductors were demonstrated (F. Reale et al., Sci. Rep. 7, 14911, 2017). Indeed, both these publications represent two extremes in 2D semiconductor properties. The former exhibits the lowest ever recorded Schottky barrier which is still governed by semi-classical current injection mechanisms, while the latter demonstrate the highest recorded mobility for lab-synthesised WS2.
The work performed within the scope of objective 2 led to the creation of a novel paradigm in the field of electron dynamics, by demonstrating the effect of extremely slow carriers on the electrostatics and transport properties of surface controlled semiconductors. The primary work published under this objective (I. Amit et al., Adv. Mater. 29, 1605598, 2017) attracted the attention of the academic world.
Some of the main scientific achievements of this action were
- The discovery of threshold voltage transient effect, which is governed by extremely slow charge carriers dynamics. This effect dominates the transport properties in semiconductors in which one dimension, or more, is lower than the Debye screening length.
- The demonstration of ultra-low Schottky barriers. These results hold immense significance for the future of infrared light detectors, and also perfectly align with the original goals of the FLAIR platform.
- The fabrication and demonstration of high optical quality and high mobility CVD-grown semiconductor which is one unit-cell thick. As a derivative of this research, high quality electrical contacts to 2D semiconductors were realised.
Each of these achievements represented a significant leap from the hitherto state-of-the-art, and all of them are applicable beyond the materials that were chosen for the demonstration. As such, the outputs of this fellowship, that are applicable to 2D semiconductors at large, establish a high-quality body of knowledge that significantly affect the scientific community’s approach to 2D materials. It is of particular interest to mention in this context the development and dissemination of the Threshold Voltage Transient Spectroscopy (TVTS). This novel methodology’s impact on academic research into 2D semiconductors is twofold. First, it provides important insight into the mechanism of current evolution through dynamic capture and emission processes of charges in surface governed conductors. Second, building on the insights gained, a new method for charge traps spectroscopy, namely TVTS, was developed and demonstrated on several 2D materials. This new method of spectroscopy will enable the academic community to obtain information that is essential for developing novel devices, without the need for a large invest in equipment.
