Few-layered titanium trisulfide (TiS3) field-effect transistors

Abstract

Titanium trisulfide (TiS₃) is a promising layered semiconductor material. Several-mm-long TiS₃ whiskers can be conveniently grown by the direct reaction of titanium and sulfur. In this study, we exfoliated these whiskers using the adhesive tape approach and fabricated few-layered TiS₃ field-effect transistors (FETs). The TiS₃ FETs showed an n-type electronic transport with room-temperature field-effect mobilities of 18–24 cm² V⁻¹ s⁻¹ and ON/OFF ratios up to 300. We demonstrate that TiS₃ is compatible with the conventional atomic layer deposition (ALD) procedure for Al₂O₃. ALD of alumina on TiS₃ FETs resulted in mobility increase up to 43 cm² V⁻¹ s⁻¹, ON/OFF ratios up to 7000, and much improved subthreshold swing characteristics. This study shows that TiS₃ is a competitive electronic material in the family of two-dimensional (2D) transition metal chalcogenides and can be considered for emerging device applications.