Highly-anisotropic carrier transport and optical properties of two-dimensional titanium trisulfide

In-plane anisotropy of two-dimensional materials remains one of the most attracting properties. By employing first-principles calculations, we systematically explore the electronic, carrier transport, and optical properties of monolayer and bilayer titanium trisulfide (TiS3). They are predicted to be direct semiconductors with eligible bandgap of about 1.4 eV. The two systems have high charge carrier mobility and exhibit highly in-plane anisotropy. The carrier mobility can achieve a large value of 10(4) cm(2) V-1 s(-1) for electron and 10(3) - cm(2) V-1 s(-1) for hole. In addition, significant anisotropies in their optical absorptions are revealed over a broad spectral range from near-infrared to near-ultraviolet light. First bright exciton state can possess a large binding energy larger than 500 meV, and light absorption coefficients are as large as 10(5) cm(-1) in the two systems. These results in monolayer and bilayer are potentially useful for designing their optoelectronic devices. [GRAPHICS] .