Correlation between charge density wave phase transition and hydrogen adsorption in 1T-TaS2thin film devices

Yasushi Ishiguro; Rintaro Suzuki; Zhao Yangzhou; Naoko Kodama; Kazuyuki Takai

doi:10.1088/1361-6528/acc8db

Correlation between charge density wave phase transition and hydrogen adsorption in 1T-TaS₂thin film devices

Nanotechnology. 2023 Apr 19;34(27). doi: 10.1088/1361-6528/acc8db.

Authors

Yasushi Ishiguro¹, Rintaro Suzuki², Zhao Yangzhou³, Naoko Kodama³, Kazuyuki Takai^{2

3}

Affiliations

¹ Department of Electrical and Electronic Engineering, Tokyo Denki University, Senju Asahi-cho 5, Adachi-ku, Tokyo, 120-8551, Japan.
² Department of Chemical Science and Engineering, Hosei University, Kajino-cho, Koganei-shi, Tokyo, 184-8584, Japan.
³ Department of Applied Chemistry, Hosei University, Kajino-cho, Koganei-shi, Tokyo, 184-8584, Japan.

PMID: 36996805
DOI: 10.1088/1361-6528/acc8db

Abstract

Thin films of tantalum disulfide in the 1T-polytype structural phase (1T-TaS₂), a type of metallic two-dimensional (2D) transition metal dichalcogenides (TMDs), are reactive to H₂. Interestingly, in the incommensurate charge-density wave (ICCDW) phase with a metallic state, the electrical resistance of the 1T-TaS₂thin film decreases when H₂is adsorbed on it and returns to its initial value upon desorption. In contrast, the electrical resistance of the film in the nearly commensurate CDW (NCCDW) phase, which has a subtle band overlap or a small bandgap, does not change upon H₂adsorption/desorption. This difference in H₂reactivity is a result of differences in the electronic structure of the two 1T-TaS₂phases, namely, the ICCDW and NCCDW phases. Compared to other semiconductor 2D-TMDs such as MoS₂and WS₂, the metallic TaS₂has been theoretically proven to capture gas molecules more easily because Ta has a stronger positive charge than Mo or W. Our experimental results provide evidence of this. Notably, this study is the first example of H₂sensing using 1T-TaS₂thin films and demonstrates the possibility of controlling the reactivity of the sensors to the gas by changing the electronic structure via CDW phase transitions.

Keywords: 2D materials; CDW phase transition; TaS2; electrical conductivity; gas-sensor; hydrogen adsorption.