Congratulation Junseok for ACS Nano acceptance!
Title: Electrical Transport Properties of Polymorphic MoS2
Authors : Kim, Jun Suk; Kim, Jaesu; Zhao, Jiong; Kim, Sungho; Lee, Jin Hee; Jin, Youngjo; Choi, Homin; Moon, Byoung Hee; Bae, Jung Jun; Lee, Young Hee; Lim, Seong Chu
Abstract : The engineering of polymorphs in two-dimensional layered materials has recently attracted significant interest. While the semiconducting (2H) and metallic (1Tʹ) phases are known to be stable in thin-film MoTe2, semiconducting 2H-MoS2 is locally converted into metallic 1T-MoS2 through chemical lithiation. In this paper, we describe the observation of the 2H, 1T, and 1Tʹ phases coexisting in Li-treated MoS2, which result in unusual transport phenomena. While multiphase MoS2 shows no transistor-gating response, the channel resistance decreases in proportion to the temperature, similar to the behavior of a typical semiconductor. Transmission electron microscopy images clearly show that the 1T and 1Tʹ phases are randomly distributed and intervened with 2H-MoS2, which is referred to as the 1T and 1Tʹ puddling phenomenon. The resistance curve fits well with 2D-variable range-hopping transport behavior, where electrons hop over 1T domains that are bounded by semiconducting 2H phases. However, near 30 K, electrons hop over charge puddles. The large temperature coefficient of resistance (TCR) of multiphase MoS2, -2.0 × 10-2 K-1 at 300 K, allows for efficient IR detection at room temperature by means of the photothermal effect