Few-layer HfS2 transistors

• Published in: Scientific reports 2016-03, Vol.6 (1), p.22277-22277, Article 22277
• Main Authors: Kanazawa, Toru, Amemiya, Tomohiro, Ishikawa, Atsushi, Upadhyaya, Vikrant, Tsuruta, Kenji, Tanaka, Takuo, Miyamoto, Yasuyuki
• Format: Article
• Language: English
• Subjects: 140/133; 639/166/987; 639/301/1005/1007; 639/925/357/1018; Experimental research; Humanities and Social Sciences; Mobility; multidisciplinary; Science; Transistors
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep22277

HfS 2 is the novel transition metal dichalcogenide, which has not been experimentally investigated as the material for electron devices. As per the theoretical calculations, HfS 2 has the potential for well-balanced mobility (1,800 cm 2 /V·s) and bandgap (1.2 eV) and hence it can be a good candidate for realizing low-power devices. In this paper, the fundamental properties of few-layer HfS 2 flakes were experimentally evaluated. Micromechanical exfoliation using scotch tape extracted atomically thin HfS 2 flakes with varying colour contrasts associated with the number of layers and resonant Raman peaks. We demonstrated the I-V characteristics of the back-gated few-layer (3.8 nm) HfS 2 transistor with the robust current saturation. The on/off ratio was more than 10 4 and the maximum drain current of 0.2 μA/μm was observed. Moreover, using the electric double-layer gate structure with LiClO 4 :PEO electrolyte, the drain current of the HfS 2 transistor significantly increased to 0.75 mA/μm and the mobility was estimated to be 45 cm 2 /V·s at least. This improved current seemed to indicate superior intrinsic properties of HfS 2 . These results provides the basic information for the experimental researches of electron devices based on HfS 2 .