Abstract
Using atomic-scale thin film of metal chalcogenide layered material, we have developed semiconducting channel for future electronics. We investigated transport properties, particularly scattering property of carrier transport. In this transport experiment, it is found that the carrier scattering from interfacial Coulomb impurities is greatly intensified in extremely thinned channels, resulting from shortened interaction distance between impurities and carriers.
Thus, we fabricated MoS2 field-effect transistors on crystalline hexagonal boron nitride (h-BN) and SiO2 substrates. Temperature dependence of these transistors shows distinct weak temperature dependence of the MoS2 devices on h-BN substrate. At the room temperature, mobility enhancement and reduced interface trap density of the single and bilayer MoS2 devices on h-BN substrate further indicate that reducing substrate traps is crucial for enhancing the mobility in atomically thin MoS2 devices. More detail of carrier scattering in the atomic-scale thin channel will be discussed.
Furthermore, we have developed field effect transistor using high-k flak dielectric with layered structure.

References
1. S.-L. Li, K.Wakabayashi, Y.Xu, Y.-F.Lin. M.Y.Chen, K.Komatsu, S.Nakaharai, A.Aparecido-Ferreira, W.W. Li, K.Tsukagoshi, Nano Letters 13, 3546 (2013).
2. M.-Y. Chan, K. Komatsu, S.-L.Li, Y.Xu, P.Darmawan, H.Koramochi, S.Nakaharai, K.Watanabe, T.Taniguchi, K.Tsukagoshi, Nanoscale,  in press (2013).
3. W.-W. Li, S.-L.Li, K.Komatsu, A.A. Ferreira, Y.-F. Lin, Y.Xu, M.Osada, T.Sasaki, K.Tsukagoshi, Applied Physics Letters 103, 023113 (2013).

Biography
Kazuhito Tsukagoshi studied experimental research on transport physics in semiconductor microstructure, completing his PhD in 1995. After that he worked as a visiting associate in Cavendish laboratory (University of Cambridge, U.K.) and then in Hitachi Cambridge Laboratory (Hitachi Europe Ltd, U.K.). In 1999, he joined RIKEN (Japan) where he carried out research on carbon nanotube and organic electronics. He continued this research in AIST in 2008, and moved to WPI-MANA, NIMS in 2009. His current research focuses on ultra-thin functional devices to realize the next generation electronics. He was awarded The MEXT Young Scientists' Prize (2006) and JSPS prize (2013).