Cover Picture: Screening and interlayer coupling in multilayer MoS2 (Phys. Status Solidi RRL 4/2013)



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After decades of relentless progress, the evolutionary path of silicon CMOS industry is finally approaching an end. Fundamental limitations do not allow silicon to scale beyond 10 nm technology node without compromising severely on the device performance. In order to reinforce the accelerating pace, there is an urgent and immediate need for alternative materials. Low-dimensional materials in general and 2D layered material in particular are extremely interesting in this context, as they not only offer the fundamental study of their unique electrical, optical, mechanical and chemical properties but also their excellent electrostatic integrity and inherent scalability make them attractive from a technological standpoint. Recently the rich family of transition metal di-chalcogenides – comprising of MoS2, WS2, WSe2 and many more – have received a lot of scientific attention as the future of nanoelectronics. In order to harvest the ultimate potential of these novel nano materials it is extremely important to evaluate the core physical enterprises that drive them. In their Letter on pp. 268–273, Saptarshi Das and Joerg Appenzeller experimentally investigated the mobility of multilayer MoS2 field effect transistors with different metal contacts. The authors found a rather interesting trend in the “effective” field effect mobility as a function of the MoS2 layer thickness which could be explained by a unique model based on Thomas–Fermi charge screening and interlayer coupling. The associated cartoon image is a medley of the experimental mobility trend and the corresponding resistor network model that explains the trend.