Electrical Transport Properties of Polymorphic MoS2

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• 作者：Jun Suk Kim ; Jaesu Kim ; Jiong Zhao ; Sungho Kim ; Jin Hee Lee ; Youngjo Jin ; Homin Choi ; Byoung Hee Moon ; Jung Jun Bae ; Young Hee Lee ; Seong Chu Lim
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：August 23, 2016
• 年：2016
• 卷：10
• 期：8
• 页码：7500-7506
• 全文大小：425K
• 年卷期：0
• ISSN：1936-086X

文摘

The engineering of polymorphs in two-dimensional layered materials has recently attracted significant interest. Although the semiconducting (2H) and metallic (1T) 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 1T′ phases coexisting in Li-treated MoS₂, which result in unusual transport phenomena. Although 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 1T′ phases are randomly distributed and intervened with 2H-MoS₂, which is referred to as the 1T and 1T′ 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.