Ultrahigh Photoresponse of Few‐Layer TiS₃ Nanoribbon Transistors

Abstract

Transition metal chalcogenides have raised a huge interest in the nanoscience and material science communities. [1][2][3] The possibility of isolating ultrathin layers of these materials opens the door to new applications and phenomena derived from the reduced dimensionality.Among the large family of semiconducting chalcogenides, Mo-and W-based dichalcogenides are the most studied materials because of their electronic and optical properties which could make them complementary materials to graphene in applications requiring optically active semiconducting materials. [4][5][6][7][8][9][10][11][12][13][14] Nonetheless, there are many other semiconducting chalcogenide materials where electronic properties, in atomically thin form, are thus far unexplored. TiS 3 , for instance, is one of the semiconducting members of the trichalcogenides family with a bulk optical bandgap of ≈ 1 eV. 15 It has a structure, shown in Figure 1(a), composed of parallel sheets of one dimensional chains of stacked triangular prisms (TiS 3 ). 16 The sheets are held together by van der Waals forces and might be exfoliated in the same manner as This is the post-peer reviewed version of the following article: J.O. Island et al. "Ultrahigh photoresponse of few-layer TiS 3 nanoribbon transistors".

TiS3nanoribbons: Width-independent band gap and strain-tunable electronic properties

“…Compared with the edge energies of graphene and many other TMC nanoribbons, which are on the order of 1 eV/Å [39,40], b-TiS 3 NRs have much lower edge energy, suggesting that formation of b-TiS 3 NRs from 2D TiS 3 could be much easier. In fact, the experimentally reported TiS 3 NRs are along the b direction [20]. The low edge energy of b-TiS 3 NRs can be attributed to the fact that the bonds along the a direction in 2D TiS 3 are much weaker than those along b, in accordance with the low in-plane stiffness (5.225 eV/Å 2 ) along this direction.…”

“…A recent theoretical study reported that the carrier mobility in 2D monolayer TiS 3 is highly anisotropic, and the electron mobility along the b direction is of the order of 10 4 cm 2 V −1 s −1 [22]. The experimentally reported mobility of TiS 3 is of the order of 10 2 cm 2 V −1 s −1 for sheets and 10 0 cm 2 V −1 s −1 for ribbons [20,21]. The deviation between theoretical and experimental values stems from the fact that the TiS 3 materials in experiment are multilayers rather than a monolayer and that the presence of defects and a substrate in the experiment can affect the mobility to a large extent.…”

“…The elastic modulus and carrier mobility of TiS 3 are strongly anisotropic, and monolayer TiS 3 is predicted to have a high electron mobility [22]. More importantly, the fabricated TiS 3 NRs show ultrahigh photoresponse and fast switching times [20].…”

“…In addition, several recent works have reported the synthesis of thin TiS 3 films and few-layer TiS 3 nanoribbons (TiS 3 NRs) [18][19][20][21]. The TiS 3 nanostructures exhibit a direct band gap of 1.1-1.2 eV, which may be interesting for possible replacement of Si in applications when high gain is needed [20].…”

“…The TiS 3 nanostructures exhibit a direct band gap of 1.1-1.2 eV, which may be interesting for possible replacement of Si in applications when high gain is needed [20]. The elastic modulus and carrier mobility of TiS 3 are strongly anisotropic, and monolayer TiS 3 is predicted to have a high electron mobility [22].…”