Speakers

The interface between two materials often plays a critical role in electronic device performance. In particular, metal–semiconductor contacts are essential to device operation. In this talk, I will present interface engineering research for devices based on transition metal dichalcogenides (TMDCs), employing solution-based chemical processes.

TMDCs are two-dimensional layered semiconductors with an atomic thickness of approximately 0.7 nm and have attracted considerable attention for a wide range of electronic device applications. For device operation, such as in field-effect transistors, the metal–TMDC contact interface is crucial for achieving efficient switching between on and off states. In this presentation, I will focus on our recent work on interface engineering, particularly on the modulation of metal contacts in TMDC devices.

TMDCs often suffer from surface Fermi-level pinning (FLP), which fixes the surface potential at the metal–TMDC interface. This phenomenon limits the tunability of the Schottky barrier height through the choice of contact metal. To address this issue, we have developed chemistry-based solution processes to insert ultrathin interfacial layers between the metal contact and TMDCs. One approach involves introducing a poly-L-lysine (PLL) polymer layer beneath the metal contacts in WSe₂ devices [1]. The PLL forms an effective thin interfacial layer on the WSe₂ surface, enabling partial suppression of FLP. In this talk, I will discuss the details of this method as well as additional material systems designed to mitigate FLP.

Furthermore, because charge carriers inevitably traverse the metal–TMDC interface during device operation, interface modification provides an opportunity to introduce device functionalities. In this context, I will also present our recent work on memristive behavior achieved through interface modulation in TMDC devices.

[1] R. Naoi, et al., ACS Appl Electro. Mater. 2025, 7, 5418.​​​​​